Obstetrics Pt.3

Question 1

How is Rubella spread?

Why is its perinatal infection uncommon?

Answer 1

• Togavirus spread by droplet transmission

- Very uncommon in the UK thanks to MMR

Question 2

Describe Rubella screening

Answer 2

• Prevalence of rubella has reached such low levels in the UK that screening is NO LONGER ROUTINELY OFFERED
• For women who are screened and rubella antibody is NOT detected, they should be offered the MMR after pregnancy
• NOTE: the vaccine itself is contraindicated in pregnancy because it is a live vaccine

Question 3

What are the clinical features of Congenital Rubella Syndrome?

Answer 3

• Sensorineural deafness
• Congenital cataracts
• Blindness
• Encephalitis
• Endocrine problems

Question 4

What is the risk of CRS?

Answer 4

• The risk of CRS decreases with gestation and the manifestations are less severe
• Rubella infection before 11 weeks has 100% risk of CRS
• Rubella infection > 20 weeks has no risk of CRS

Question 5

What is the management of CRS?

Answer 5

• If infection during pregnancy is confirmed, risk of CRS should be assessed
• If it has occurred < 16 weeks, termination of pregnancy should be offered

Question 6

What is Syphilis and its clinical features?

Answer 6

• Caused by Treponema pallidum

Clinical Features
- Painless genital ulcer 3-6 weeks after infection is acquired (condylomata lata)

• NOTE: this may be on the cervix and hence go unnoticed
• Secondary manifestations occur 6 weeks to 6 months after infection with a maculopapular rash or lesions affecting the mucous membranes
• If untreated, some will develop symptomatic cardiovascular tertiary syphilis and some will develop neurosyphilis
• In pregnant women with early, untreated syphilis, most infants will be infected and 25% will be stillborn

Question 7

What are the risks of syphilis in pregnancy?

Answer 7

• FGR
• Foetal hydrops
• Congenital syphilis (may cause long-term disability)
• Stillbirth
• Preterm birth
• Neonatal death
• IMPORTANT: adequate treatment with benzathine penicillin markedly improved the outcome for the foetus

Question 8

Describe Syphilis Screening in pregnancy

Answer 8

• Routine antenatal screening is offered for ALL pregnant women
• Treponemal antibodies are detected in serology
• Non-treponemal tests detect non-specific treponemal antibodies
  
  • Venereal disease research laboratory (VDRL) test
  • Rapid plasma reagin test (RPR)
  • NOTE: they have a high false-positive rate
• Treponemal tests detect specific treponemal
  
  • EIAs
    
    • Very sensitive and specific
  • Treponema pallidum haemagglutination assay (TPHA)
  • Fluorescent treponemal antibody-absorbed test (FTA-abs)
• IMPORTANT: none of these tests will detect syphilis in the incubation stage

Question 9

What is the management of syphilis in pregnancy?

Answer 9

• Confirm the diagnosis and test for other STIs
• GUM clinic should initiate appropriate contact tracing
• Parenteral penicillin (benzathine penicillin) has a 98% success rate at preventing congenital syphilis
• A Jarish-Herxheimer reaction may occur with treatment as a result of the release of proinflammatory cytokines in response to dying organisms
  
  • Causes worsening of symptoms and fever for 12-24 hours after starting treatment
  • May be associated with uterine contractions and foetal distress
  • So, women may be admitted during treatment for monitoring
• If the woman is NOT treated during pregnancy, the baby should be treated after delivery immediately

Question 10

What is Toxoplasmosis?

Answer 10

• Caused by Toxoplasma gondii which is a protozoan found in cat faeces, soil or uncooked meat
• 1/3 of people in the UK are probably infected with Toxoplasma at some point in their lives

Question 11

Is toxoplasmosis screening offered?

Answer 11

• NOT offered routinely because it is very rare for babies to be affected
• Little evidence for the benefits of screening

Question 12

What is some advice about toxoplasmosis prevention?

Answer 12

• Avoiding eating rare or raw meat
• Avoiding handling cats and cat litter
• Wearing gloves and washing hands when gardening or handling soil

Question 13

What are the clinical features of toxoplasmosis?

How does foetal damage and transmission rate change during pregnancy?

Answer 13

• Initial infection is usually ASYMPTOMATIC or may cause flu-like illness
• Parasitaemia occurs within 3 weeks
• Infection in the first trimester is most likely to cause severe foetal damage but the transmission rate is low (10%)
• In the third trimester, the transmission rates are much higher (85%) but the risk of foetal damage is low (10%)

Question 14

What are the features of Severely Affected Infants of Toxoplasmosis?

Answer 14

• Ventriculomegaly
• Microcephaly
• Chorioretinitis
• Cerebral calcification
• NOTE: most infants are asymptomatic at birth and develop symptoms later on

Question 15

What is the management of toxoplasmosis?

Answer 15

`- Diagnosis is made by the Sabin Feldman Dye Test

• NOTE: IgM antibody tests are also available but IgM may persist for months or years after infection
• If an abnormal US raises suspicion of congenital toxoplasmosis, amniocentesis can be performed
• PCR of amniotic fluid is highly accurate for identification of T. gondii
• Spiramycin treatment can be used in pregnancy (3 week course of 2-3 g/day)
• This reduces incidence of transplacental infection
• If toxoplasmosis is found to be the cause of abnormalities on ultrasound, termination of pregnancy should be offered

Question 16

What is cytomegalovirus?

Answer 16

• CMV is a DNA herpes virus transmitted by the respiratory droplet route and excreted in the urine
• 60% of women are seropositive for CMV when they become pregnant
• 1-2 out of 200 infants in the UK are born with congenital CMV
• Some will have problems at birth (e.g. hearing loss, learning difficulties) and others will be asymptomatic but go on to develop problems later on
• Primary infection is more likely to cause congenital CMV

Question 17

What are the clinical features of cytomegalovirus?

Answer 17

• Primary infection usually produces no symptoms or mild flu-like symptoms in the mother
• Diagnosis is usually made after abnormalities are seen on the ultrasound
• Features in the foetus
  
  • Growth restriction
  • Microcephaly
  • Intracranial calcification
  • Ventriculomegaly
  • Ascites
  • Hydrops
• Infants may present later with blindness, deafness or developmental delay
• The neonate can also be anaemic and thrombocytopaenic with hepatosplenomegaly, jaundice and a purpuric rash

Question 18

What is the management of CMV?

Answer 18

• Serological diagnosis (CMV antibodies in an initially seronegative woman)
• NOTE: IgM can persist for several months so IgM is insufficient to diagnose infection, it has to be a new finding in a woman who was IgM negative at the time of booking
• The amniotic fluid can be tested by PCR
• If abnormalities suggestive of congenital CMV are detected, termination of pregnancy should be discussed
• CMV is a herpes virus, so it can be latent and be reactivated
• It persists in the lymphocytes throughout life
• Reactivation occurs via shedding in the genital, urinary or respiratory tract

Question 19

What virus causes chickenpox?

What can chickenpox cause?

Answer 19

• Caused by varicella zoster virus (VZV) which is transmitted by droplets and direct personal contact
• Screening is NOT routinely recommended
• Women identified as being seronegative can be considered for vaccination either prepregnancy or in the postnatal period
• It can cause foetal varicella syndrome

Question 20

What are complications of chickenpox in pregnant women?

Answer 20

• Pneumonia
• Hepatitis
• Encephalitis
• Non-immune pregnant women are more vulnerable to complications of chicken pox
• The mortality rate is 5 times high in pregnant women compared to non-pregnant adults

Question 21

What is the advice for pregnant women regarding chickenpox?

Answer 21

• Asked whether they have had chickenpox before at the booking visit
• If NOT, be advised to avoid contact during pregnancy
• If they do come into contact with chickenpox, they should seek medical advice ASAP
• Significant contact is defined as being in the same room as someone for 15 mins or more, or face-to-face contacts
• Individuals with the virus are infectious 48 hours prior to the appearance of the rash until the vesicles crust over (around 5 days)
• VZV IgG can be detected to confirm VZV immunity

Question 22

How should non-immune women with chickenpox be managed?

Answer 22

• Given VZIG as soon as possible
  
  • It is effective when given up to 10 days after contact
• Women should be advised to inform the doctor if a rash develops

Question 23

How is chickenpox in pregnancy managed?

Answer 23

• Avoid contact with other pregnant women and neonates until the lesions have crusted over
• Aciclovir 800 mg 5/day for 7 days should be prescribed if they present within 24 hours of the onset of the rash and they are > 20 weeks gestation
• VZIG has NO therapeutic benefit once chickenpox has developed
• Hospital admission should be considered if the following risk factors are present: smoking, chronic lung disease, corticosteroids or in latter half of pregnancy
• Women who are hospitalised should be nursed in isolation from babies and pregnant women
• Delivery during the viraemic period may be EXTREMELY HAZARDOUS
• Patients should be given supportive treatment with IV aciclovir

Question 24

What are the risks of chickenpox in pregnancy?

Answer 24

• Thrombocytopaenia
• DIC
• Hepatitis
• Varicella infection of the newborn

Question 25

What is Congenital Varicella Syndrome?

Answer 25

• Characterised by one or more of the following:
  
  • Skin scarring in a dermatomal distribution
  • Eye defects (microphthalmia, chorioretinitis, cataracts)
  • Hypoplasia of the limbs
  • Neurological abnormalities (microcephaly, cortical atrophy, mental restriction and dysfunction of bowel and bladder sphincters)
• This occurs in a minority of infected foetuses (1%)
• No cases have been reported if maternal infection has occurred after 28 weeks
• If the mother has contracted chickenpox during the pregnancy, referral to foetal medicine specialist should be considered at 16-20 weeks or 5 weeks after infection for discussion and detailed ultrasound examination
  
  • NOTE: 5 week time lag is required as it takes time for features to manifest

Question 26

How should maternal infection around the time of delivery be managed?

Answer 26

• Significant risk of varicella of the newborn
• Elective delivery should be avoided until 5-7 days after the onset of the rash to allow time for passive transfer of antibodies to the foetus
• Neonatal ophthalmic examination done after birth
• If birth occurs within 7 days of the onset of the rash or the mother develops chickenpox within 7 days of delivery, the neonate should be given VZIG
• The infant should be monitored for signs of infection until 28 days after the onset of maternal infection
• Neonatal infection should be treated with aciclovir

Question 27

Is contact with shingles a problem?

Answer 27

• Low risk of a non-immune pregnant woman getting chickenpox from someone with shingles

Question 28

What is parvovirus infection and how is it transmitted?
What percentage of women are immune?
Is screening recommended?

Answer 28

• Caused by parvovirus B19 which is transmitted through respiratory droplets
• 50% of women of child-bearing age are immune and 50% are susceptible
• Routine screening is NOT recommended

Question 29

What are the clinical features of parvovirus?
When is the foetus most vulnerable?
What are complications of the virus and how is this investigated?

Answer 29

• Asymptomatic or cause a mild flu-like illness and/or arthropathy
• In children it causes slapped cheek syndrome (aka fifth disease, erythema infectiosum)
• Foetus is most vulnerable in the second trimester
• In most foetuses infected with parvovirus, there will be spontaneous resolution with no long-term sequelae
• However, the infection can cause aplastic anaemia
• The anaemic foetus could be come hydropic due to high output cardiac failure and liver congestion
• Seen on ultrasound (high velocity in the foetal middle cerebral artery suggests anaemia)

Question 30

How is parvovirus diagnosed?
When is foetal loss due to virus higher?
How is the virus managed?

Answer 30

• Diagnosed by serology in mother (development of IgM antibodies to Parvovirus B19) having previously tested negative
• PCR of virus in maternal and foetal serum/amniotic fluid is the most accurate test
• A hydropic foetus may recover spontaneously or may require in utero transfusion
• Infection in the first 20 weeks can lead to hydrops fetalis and intrauterine death (intrauterine transfusion is not possible at early gestations)
• Foetal loss rate is much higher (10%) in the first 20 weeks
• If the anaemia is treated by in utero transfusions, the foetus can make a complete recovery
• Parvovirus does NOT cause neurological damage so if they survive the anaemia the outcome is usually normal

Question 31

What is Listeria?

Where does it originate?

Answer 31

• Caused by Listeria monocytogenes which is an aerobic and facultatively anaerobic motile Gram-positive bacillus
• It is an obligate intracellular parasite
• People with reduced cell-mediated immunity (i.e. pregnant women) are most at risk
• Incidence of Listeria infection in pregnant women is 18 x higher than in the non-pregnant population
• Usually comes from contaminated food, most commonly:
  
  • Unpasteurised milk
  • Ripened soft cheeses
  • Paté
• Listeria does NOT survive in cooked or frozen food but can survive in refrigerated food (e.g. milk, soft cheese, prawns)

Question 32

What are the clinical features of Listeria?
How does transmission to the foetus occur?
What are Listeria complications in pregnancy?

Answer 32

• Flu-like illness with fever and general malaise
• 1/3 of women will be asymptomatic
• Transmission to the foetus can occur via:
  
  • Ascending route through the cervix
  • Transplacental
• 20% of affected pregnancies result in miscarriage or stillbirth
• 50% result in premature delivery
• 38% neonatal mortality (due to respiratory distress, fever, sepsis or neurological symptoms)

Question 33

What is the management of Listeria?

Answer 33

• Diagnosed by isolation of the organism from blood, vaginal swabs or the placenta
• Meconium staining of amniotic fluid may raise suspicion
• IV antibiotics (AMPICILLIN 2 g every 6 hours)

Question 34

What is Malaria?
Which pregnant women have increased risk of malaria?
Why may the parasite be missed in blood films?

Answer 34

• Plasmodium falciparum carries the worse prognosis for mother and foetus
• Most common in sub-Saharan Africa
• Pregnant women have an increased risk of infection (especially if primiparous)
• The parasite can sequestrate in the placenta (and be missed by blood films)

Question 35

What are the clinical features of Malaria?

Answer 35

• Pyrexia
• Associated with miscarriage and preterm labour
• Hypoglycaemia is common and may be severe in pregnancy
• Pulmonary oedema can occur (high mortality)
• Jaundice
• Renal failure

Question 36

What are the effects of Malaria on the foetus?

Answer 36

• Preterm delivery
• FGR
• Higher rate of HIV transmission

Question 37

What is the management of Malaria?

Answer 37

• Symptomatic and supportive treatment
• Antimalarials (depends on drug resistance and local patterns of disease)
• Pregnant women planning to travel to endemic areas should be counselled about insecticides, mosquito nets and appropriate clothing

Question 38

Describe herpes in pregnancy

Answer 38

• This is DANGEROUS if acquired around the time of delivery
• Double-stranded DNA virus
• Neonatal herpes has a high morbidity and mortality
• It occurs due to contact with infected secretions

Question 39

What are the clinical features of herpes?

What are the subgroups of neonatal herpes?

Answer 39

• Genital herpes causes ulcerative lesions on the vulva, vagina and cervix
• Primary infection is usually more severe and can cause systemic symptoms and urinary retention
• Neonatal herpes can be caused by HSV1 and HSV2
• Neonatal herpes has THREE subgroups:
  
  • Localised to the skin, eye and mouth
  • Local central nervous system disease (encephalitis alone)
  • Disseminated infection with multiple organ involvement
• Risk is greatest when the woman acquires a new infection (primary genital herpes) particularly within 6 weeks of delivery

Question 40

What is the general management of herpes?

Answer 40

• Swab to diagnose HSV
• If herpes suspected, refer to a genitourinary physician to confirm the diagnosis by viral culture and PCR
• Aciclovir (400 mg tds) is recommended
• For women presenting within 6 weeks of expected delivery, type-specific HSV antibody testing is advisable

Question 41

What is the management of primary infections of herpes in pregnancy?

Answer 41

• If the infection occurs before the 6 weeks prior to expected delivery, the pregnancy should be managed expectantly and vaginal delivery anticipated
• C-section for ALL women developing first-episode genital herpes in the 3rd trimester (particularly if within 6 weeks of delivery)
• If the woman chooses vaginal delivery, rupture of membranes and invasive procedures should be avoided
• IV aciclovir should be given intrapartum to the mother

Question 42

What is the management of recurrent episodes of herpes?

Answer 42

• Aciclovir 400 mg tds considered from 36 weeks gestation
• Recurrent episodes occurring during pregnancy is NOT an indication for delivery by C-section
• Invasive procedures during labour should be avoided if there are genital lesions

Question 43

What is Group B Streptococcus?

When does transmission occur?

Answer 43

• Streptococcus agalactiae is a Gram-positive coccus
• It is a vaginal commensal that can cause sepsis in the neonate
• Transmission occurs between the time of rupture of membranes to delivery
• It is the most common cause of severe early-onset (within 7 days of delivery) infection in newborns
• 21% of women carry GBS as a commensal
• Routine screening is NOT carried out in the UK

Question 44

What are the clinical features of Group B Streptococcus?

Answer 44

• The mother does NOT experience symptoms because GBS is a commensal
• Sepsis in the neonate
  • Collapse
  • Tachypnoea
  • Nasal flaring
  • Poor tone
  • Jaundice

Question 45

What is the management of Group B Streptococcus?

Answer 45

• Antenatal
  
  • If detected incidentally, antenatal treatment is NOT recommended because it does not reduce the likelihood of GBS colonisation at the time of delivery
• Intrapartum antibiotic prophylaxis
  
  • Infection of the neonate occurs during labour
  • Antibiotics (penicillin or clindamycin) given in labour are 60-80% effective in reducing early-onset neonatal GBS infection
  • IV penicillin 3 g should be given as soon as possible after the onset of labour and 1.5 g four-hourly until delivery
  • Clindamycin 900 mg should be given IV 8 hourly if allergic to penicillin
• Women undergoing an elective C-section in the absence of labour or membrane rupture do NOT need antibiotic prophylaxis

Question 46

What are risk factors requiring GBS prophylaxis?

Answer 46

• Intrapartum fever
• Prolonged rupture of membranes greater than 18 hours
• Prematurity less than 37 weeks
• Previous infant with GBS
• Incidental detection of GBS in current pregnancy
• GBS bacteriuria

Question 47

How does GBS affect the Neonate?

Answer 47

• Symptoms occur at or soon after birth
• Neonatal sepsis can rapidly kill
• Blood cultures should be obtained before antibiotics are commenced
• Antibiotics should be given based on trust guidelines

Question 48

What is Chlamydia caused by?
Is there screening?
When does transmission occur and what are complications of chlamydia in the infant?

Answer 48

• Caused by Chlamydia trachomatis which is an obligate intracellular organism
• NOT routinely screened
• Women under the age of 25 booking for antenatal care should be informed about the National Screening Programme
• Transmission occurs at the time of delivery
• Transmission can cause conjunctivitis and pneumonia in the infant

Question 49

What are the clinical features of chlamydia in pregnancy?

What are the pregnancy risks?

Answer 49

• Often asymptomatic in pregnancy
• Risks
  • Preterm rupture of membranes
  • Preterm delivery
  • LBW

Question 50

What is the management of chlamydia?

Answer 50

• Azithromycin or erythromycin

- NOTE: tetracyclines should be avoided in pregnancy

Question 51

What is gonorrhoea caused by?

How does infection present?

Answer 51

• Caused by Neisseria gonorrhoeae which is a Gram-negative diplococcus
• Infection is often asymptomatic or may present with mucopurulent discharge or dysuria
• Transmission occurs at the time of delivery and can cause ophthalmia neonatorum

Question 52

What are the risks of gonorrhoea?

Answer 52

• Preterm rupture of membranes

- Preterm birth

Question 53

What is the management of gonorrhoea?

Answer 53

• Bacteriological swabs should be taken
• Cephalosporins are effective against gonococcus
• Empirical treatment for chlamydia should also be considered
• Contact tracing should be arranged via a GUM clinic

Question 54

When does HIV transmission occur?

Answer 54

• Vertical transmission mainly occurs in the late third trimester, during labour, delivery or breast feeding
• Part of routine antenatal screening

Question 55

What are clinical features of HIV?

Answer 55

• Begins with an asymptomatic stage
• Followed by gradual compromise of immune function leading to AIDS
• The interval from HIV to AIDS can be very long

Question 56

What is the management of HIV in the mother?

Answer 56

• The risk of vertical transmission is affected by maternal viral load, obstetric factors and infant feeding
• Reducing the risk of vertical transmission
  
  • Antiretroviral therapy (antenatally and intrapartum in the mother, for the first 4-6 weeks of life for the baby)
  • Delivery by elective C-section in the presence of high viral load
  • Avoid breastfeeding
• Planned vaginal delivery is possible if mother’s viral load < 50 copies/mL at 36 weeks gestation
• C-section recommended in women with hepatitis C coinfection
• Women with a high viral load should receive IV azidothymidine (AZT) if they are undergoing a planned C-section or present with spontaneous rupture of membranes

Question 57

What is the management of HIV in the infant?

Answer 57

• Cord clamped ASAP and the baby bathed immediately after birth
• Advised not to breastfeed baby
• All infants given azidothymidine for 4-6 weeks after birth
• Neonates test positive for HIV antibodies because of passive transfer from the mother
• HIV diagnosis in the neonate requires PCR (normally carries out at birth, 3 weeks, 6 weeks and 6 months)

Question 58

What Hepatitis B and how is it mainly transmitted?
Is it part of the routine screening?
How can transmission be prevented?

Answer 58

• DNA virus that is mainly transmitted in the blood, but also saliva, semen and vaginal fluid
• It is part of the routine screening for pregnant women
• High rate of vertical transmission in women who are positive for HBeAg
• Transmission is 95% preventable through administration of the vaccine and immunoglobulin at birth

Question 59

What are the clinical features of Hepatitis B?

Answer 59

• Many people have no symptoms

- The incubation period can be 6 weeks to 6 months

Question 60

How and when can HepB vertical transmission be reduced?

Answer 60

• Hepatitis B immunoglobulin and the vaccine help reduce vertical transmission
• The immunoglobulin should be given immediately after delivery
• The vaccine is given at birth, 1 month and 6 months

Question 61

In what conditions is the risk of HepC transmission increased?
Is HepC included in routine screening?

Answer 61

• Risk of transmission is higher in HIV co-infection

- NOT part of routine screening

Question 62

What are the clinical features of Hepatitis C?

Answer 62

• Can lead to cirrhosis and hepatocellular carcinoma

- 80% are asymptomatic

Question 63

What is the management of Hepatitis C?

Answer 63

• Detect anti-HCV antibodies
• Confirm with PCR for the virus
• In non-pregnant adults, administer interferon and ribavirin (CONTRAINDICATED in pregnancy)

Question 64

What are the three stages of labour?

Answer 64

• 1st STAGE: begins with the onset of contractions and ends when full cervical dilatation has been reached
• 2nd STAGE: begins with full cervical dilatation and ends with the birth of the baby
• 3rd STAGE: begins with the birth of the baby and ends with complete delivery of the placenta and membranes

Question 65

What are the 3Ps of Labour?

Answer 65

• Powers
• Passage
• Passenger
• If any of these three are abnormal, it is likely to result in an abnormal delivery

Question 66

What are the boundaries of the pelvic inlet?

Read Netters Flashcards

Answer 66

• Anteriorly - upper border of the symphysis pubis
• Laterally - upper margin of the pubic bone, ileopectineal lien and the ala of the sacrum
• Posteriorly - promontory of the sacrum

Question 67

What are the normal diameters of the pelvic inlet? (Read Netters Flashcards)

Answer 67

• Transverse = 13.5 cm
• Anterior-posterior = 11.0 cm
• The foetal head usually enters the pelvis orientated in the transverse position

Question 68

What is the angle of the pelvic inlet?

Answer 68

• The angle of the inlet is normally 60 degrees to the horizontal
• NOTE: this can be higher in Afro-Caribbean women

Question 69

What is the midpelvis?

Answer 69

• Described as the area bounded anteriorly by the middle of the symphysis pubis , laterally by the pubic bones, the obturator fascia and the inner aspect of the ischial bone and spines, and posteriorly by the junction of the second and third sections of the sacrum
• The midpelvis is almost round (similar transverse and anterior-posterior diameter of around 12 cm)

Question 70

Why are the ischial spines of the midpelvis palpable vaginally?

Answer 70

• To assess descent of the presenting part on vaginal examination
  
  • Station zero is at the level of the ischial spines
  • Instrumental delivery is only possible if the foetal head has reached the level of the ischial spines or below
• To provide a local anaesthetic pudendal nerve block (this may be used for a vacuum or forceps delivery)

Question 71

What are the boundaries of the pelvic outlet?

Answer 71

• Anteriorly - lower margin of the symphysis pubis
• Laterally - descending ramus of the pubic bone, ischial tuberosity and the sacrotuberous ligament
• Posteriorly - last piece of the sacrum

Question 72

What are the diameters of the pelvic outlet?

Answer 72

• Anterior-posterior = 13.5 cm
• Transverse = 11 cm
• IMPORTANT: this means that at the inlet, the transverse diameter is widest, then at the outlet, the AP diameter is widest. This means that the foetal head must rotate from a transverse to AP position as it passes through the pelvis
  
  • This usually happens at the midpelvis where the dimensions are roughly equal

Question 73

How does the pelvic shape change at the end of the third trimester?

Answer 73

• Pelvic ligaments loosen towards the end of the third trimester, the pelvis becomes more flexible and the diameters may increase during labour
• The pelvic dimensions can also be enhanced by changing the maternal position during labour

Question 74

What are some of the different pelvic shapes?

Answer 74

• The gynaecoid pelvis is the most favourable for labour and is also the MOST COMMON
• The android-type pelvis predisposes to failure of rotation and deep transverse arrest
• The anthropoid pelvis encourages an occipito-posterior position
• A platypelloid pelvis is also associated with an increased risk of obstructed labour due to failure of the head to engage, rotate or descend

Question 75

What is the pelvic floor and how does it affect the foetal head? (Read Netters Flashcards)

Answer 75

• Formed by the two levator ani muscles which form a musculofascial gutter during the 2nd stage of labour
• This encourages the foetal head to flex and rotate as it descends from the midpelvis to the pelvic outlet

Question 76

What is the perineum?

Answer 76

• This is the final obstacle
• The perineal body is a mass of fibrous and muscular tissue lying between the vagina and the anus
• This is relatively resistant in the nulliparous woman
• Vaginal birth may result in tearing or an episiotomy
• The perineum is more stretchy in multiparous women, resulting in faster labour

Question 77

What is the foetal skull made out of?

Answer 77

• Vault
• Face
• Base

Question 78

How are the sutures described in a foetus?

Answer 78

• At the time of labour the sutures of the vault are soft, unossified membranes
• The sutures of the face and skull base are firmly united
• The sutures allow the bones to move and overlap

Question 79

What is the vault composed of?

Answer 79

• The vault is composed of the parietal bones and parts of the occipital, frontal and temporal bones

Question 80

What are between the bones of the vault?

Answer 80

4 membranous structures

• Sagittal
• Frontal
• Coronal
• Lambdoidal

Question 81

What are fontanelles?

Answer 81

• Fontanelles are the junctions of the sutures

Question 82

Where is the anterior fontanelle?

Answer 82

• The anterior fontanelle (aka bregma) is at the junction of the sagittal, frontal and coronal sutures

Question 83

Where is the posterior fontanelle?

Answer 83

• The posterior fontanelle lies at the junction of the sagittal suture and the lambdoidal suture (this is smaller and triangular)

Question 84

Why are foetal bones in the skull compressible?

Answer 84

• Allows moulding to occur as the head passes through the pelvis

Question 85

What may severe moulding or moulding early in labour be due to?

Answer 85

• Obstructed labour
• Foetal malposition (failure of the head to rotate)
• Cephalopelvic disproportion (mismatch between the size of the foetal head and maternal pelvis)

Question 86

What is the vertex?

Answer 86

• The vertex is the area bounded by the two parietal bones and the anterior and posterior fontanelles
• In normal labour, this is the presenting part

Question 87

What is the posterior fontanelle used to define?

Answer 87

• The position of the foetal head in relation to the pubic symphysis
• By feeling the position of the anterior and posterior fontanelles on vaginal examination, the foetal head position during labour can be ascertained

Question 88

Which position is most favourable for spontaneous vaginal birth?

Answer 88

• Occipito-anterior (OA) position

Question 89

Which position is a malposition that may result in prolonged labour, instrumental delivery or C-section?

Answer 89

• Occipito-transverse (OT) position

Question 90

What is the shape of the foetus’ head?

Answer 90

• Ovoid

Question 91

What does the attitude of the foetal head mean?

Answer 91

• The attitude of the foetal head refers to the degree of flexion and extension of the upper cervical spine
• Different longitudinal diameters are presented to the pelvis depending on the attitude of the femoral head
• With further extension of the head, the occipito-frontal diameter presents

Question 92

What is the greatest longitudinal diameter which a foetus may present with?

Answer 92

• The mento-vertical and is around 13 cm

- This is known as brow presentation and is usually too large to pass through the normal pelvis

Question 93

What is a face presentation?

Answer 93

• The submento-bregmatic diameter is from below the chin to the anterior fontanelle (roughly 9.5 cm)
  
  • This is called face presentation
  • This can deliver vaginally when the chin is anterior (mento-anterior position)

Question 94

Describe the general physiology of labour

Answer 94

• The trigger that initiates human labour is poorly understood
• The cervix, which is initially long, firm and closed with a protective mucus plug must soften, shorten, thin out (effacement) and dilate for labour to progress
• The uterus must change from a state of relaxation to an active state of regular, strong, frequent contractions to facilitate transit of the foetus through the birth canal

Question 95

What happens to the Uterus during labour?

Answer 95

• Prostaglandins and oxytocin increase intracellular calcium ions, thereby stimulating contraction
• Beta-adrenergic compounds and CCBs do the opposite
• Unique to the uterus, the actin-myosin interaction occurs along the full length of the filaments so that there is a degree of shortening with each successive interaction
• This progressive shortening is called retraction and occurs in the upper part of the uterus
• This results in the development of the thicker, actively contracting ‘upper segment’
• Meanwhile, the lower segment of the uterus becomes thinner and more stretched
• This will eventually result in the cervix being taken up (effacement) into the lower segment of the uterus thereby forming a continuum for the passage of the foetus
• There are gap junctions between myometrial cells in the uterus which facilitates the passage of various products of metabolism and electrical current between cells
• These gap junctions are absent during pregnancy but appear in abundance at term
• The increase in the number of gap junctions allows greater coordination of myocyte activity
• Prostaglandins stimulate the formation of gap junctions
• Uterine contractions are involuntary
• Frequency of contractions varies during labour and with parity
• Through most of labour, they occur at intervals of 2-4 minutes
  
  • This is described in terms of frequency within a 10-minute period (e.g. 2 in 10)
• The duration of contractions varies from 30-60 seconds
• The frequency of contractions can be recorded using a CTG
• The amplitude of intrauterine pressure generated with each contraction ranges from 30-60 mm Hg

Question 96

What happens to the Cervix during labour?

Answer 96

• Contains myocytes and fibroblasts separated by ECM
• Interactions between ECM components keeps the cervix closed early in pregnancy
• Under the influence of hormonal mediators (e.g. prostaglandins), there is an increase in proteolytic activity and a reduction in collagen and elastin
• Interleukins cause pro-inflammatory changes with significant invasion of neutrophils
• Dermatan sulphate is replaced by hyaluronic acid (more hydrophilic) resulting in an increase in water content of the cervix
• This leads to cervical softening/ripening so that when contractions begin, they can bring about effacement and dilatation

Question 97

How does progesterone maintain uterine relaxation?

Answer 97

• Suppresses prostaglandin production
• Inhibits communication between myometrial cells
• Prevents oxytocin release

Question 98

What does oestrogen do prior to labour?

Answer 98

• Oestrogen opposes the action of progesterone
• Prior to labour, there is a decrease in progesterone receptors and an increase in oestrogen concentration relative to progesterone
• Prostaglandin synthesis by the chorion and decidua is enhanced, leading to an increase in calcium in the myometrial cells
• The changes in hormones also increases gap junction formation

Question 99

Where is CRH produced and what is its action before labour?

Answer 99

• In the placenta

- Potentiates prostaglandins and oxytocin for myometrial contractility

Question 100

What produces oxytocin and cortisol before labour and what are their actions?

Answer 100

• Production of oxytocin and cortisol by the foetus also stimulates the conversion of progesterone to oestrogen

Question 101

As labour becomes established, what increases the output of oxytocin?

Answer 101

• Ferguson reflex

Question 102

What is the ferguson reflex?

Answer 102

• This is a phenomenon where pressure from the foetal presenting part against the cervix is relayed via a reflex arc and results in increased oxytocin release from the maternal pituitary gland
• This stimulates uterine contractions, which, in turn, increases pressure on the cervix

Question 103

How is labour diagnosed?

Answer 103

• Strong regular painful contractions resulting in progressive cervical change
• In practice, a diagnosis is confirmed when a woman presents with contraction-like pains and the midwife performs a vaginal examination revealing effacement and dilatation of the cervix
• Loss of a ‘show’ (blood-stained plug of mucus passed from the cervix) or spontaneous rupture of membranes does NOT define labour

Question 104

How long is someone’s first labour?

Answer 104

• 8 hours

Question 105

How long is someone’s 2nd labour?

Answer 105

• 5 hours

Question 106

What is the definition of the 1st stage of labour?

Answer 106

• Defined as the time from the diagnosis of labour to full dilatation of the cervix (10 cm)

Question 107

What are the two phases of the 1st stage of labour?

Answer 107

• Latent phase- ime between the onset of regular painful contractions and 3-4 cm cervical dilatation
  
  • The cervix becomes fully effaced
  • Effacement is a process by which the cervix shortens and becomes incorporated into the lower segment of the uterus
  • Effacement may begin in the weeks before the onset of labour but is complete by the end of the latent phase
  • Effacement and dilatation occur as consecutive events in the nulliparous woman (but may occur simultaneously in the multiparous woman)
  • Dilatation is expressed in centimetres from 0 to 10 cm
  • The latent phase usually lasts from 3-8 hours
• Active phase- time between the end of the latent phase (3-4 cm dilatation) and full cervical dilatation (10 cm)
  
  • Usually lasts 2-6 hours (shorter in multiparous women)
  • Rate of cervical dilatation is considered abnormal if it is < 1 cm in 2 hours

Question 108

What is the definition of the 2nd stage of labour?

Answer 108

• Defined as the time from full dilatation of the cervix to delivery of the foetus

Question 109

What are the two phases of the 2nd stage of labour?

Answer 109

• Passive Phase - time between full dilatation and the onset of involuntary expulsive contractions
  
  • There is NO maternal urge
  • Foetal head is relatively high in the pelvis
  • Duration of 1-2 hours is recommended to allow the head to rotate and descend before active pushing
• Active Second stage
  
  • There is maternal urge to push because the foetal head is low causing a reflex to bear down
  • This should last no longer than 2 hours in a nulliparous woman

Question 110

What is the third stage?

Answer 110

• From delivery of the foetus until complete delivery of the placenta and membranes
• The placenta is usually delivered within minutes of the baby
• The third stage lasting > 30 mins is considered abnormal (unless the woman has opted for ‘physiological management’

Question 111

What is engagement?

Answer 111

• The foetal head normally enters the pelvis in the transverse position
• Engagement is said to have occurred when the widest part of the presenting part has passed successfully through the pelvic inlet
• In most nulliparous women, this will have occurred prior to labour
• If > 2/5 of the foetal head is palpable abdominally, the head is NOT yet engaged

Question 112

Describe descent

Answer 112

• During the first stage and passive second stage, descent results from uterine contractions
• In the active second stage, voluntary efforts by the mother help push the foetus along

Question 113

Describe flexion

Answer 113

• As the head descends into the narrower midpelvis, flexion of the head occurs
• This reduces the presenting diameter of the foetal head

Question 114

What is internal rotation?

Answer 114

• If the head is well flexed, the occiput will be the leading point
• As it reaches the sloping gutter of the levator ani muscles, it will be encouraged to rotate anteriorly so that the sagittal suture lies in the AP diameter of the pelvic outlet
• If the foetus is engaged in the OP position, internal rotation can occur to an OA position (this may increase duration of labour as it is a longer internal rotation)
• Alternatively, the OP position may persist resulting in a ‘face to pubes’ delivery
• This may result in obstructed labour

Question 115

What is extension?

Answer 115

• After internal rotation, the occiput is beneath the pubic symphysis and the bregma is near the lower border of the sacrum
• The flexed head then extends
• The occiput escapes from underneath the pubic symphysis and distends the vulva
• This is called crowning of the head
• The head extends further and the bregma, face and chin appear in succession over the posterior vaginal opening and the perineal body
• Some degree of perineal tearing may occur

Question 116

What is restitution?

Answer 116

• When the head is delivering, the occiput is directly anterior
• After it has crossed the perineum, the head realigns itself with the shoulders which have entered the pelvis in an oblique position
• This is a very slight movement (through 1/8 of a circle)

Question 117

What is external rotation?

Answer 117

• To be delivered, the shoulders rotate into the direct AP plane
• When this happens, the occiput rotates further and into the transverse position

Question 118

Describe delivery of the shoulders and foetal body

Answer 118

• After restitution and external rotation have occurred, the shoulders will be in the AP position
• The anterior shoulder (under the pubic symphysis) delivers first, followed by the posterior shoulder
• Traction may be applied by pulling downwards on the foetal head to help release the anterior shoulder from beneath the pubic symphysis
• The rest of the foetal body is usually delivered quite easily

Question 119

What should be included in the history when managing normal labour?

Answer 119

• Previous births and size of previous babies
• Previous C-section
• Onset, frequency, duration and perception of strength of contractions
• Whether membranes have ruptured and, if so, colour and amount of amniotic fluid lost
• Presence of abnormal vaginal discharge or bleeding
• Recent activity of the foetus (foetal movement)
• Medical or obstetric issues of notes (e.g. diabetes, hypertension, FGR)
• Any special requirements
• Maternal expectations of labour and delivery
• Birth preferences or birth plan

Question 120

What should be included in the general examination when managing normal labour?

Answer 120

• BMI- High BMI may complicate labour
• Temperature, pulse and blood pressure should be recorded
• Urine tested for protein, blood, ketones, glucose and nitrates

Question 121

What should be included in the abdominal examination when managing normal labour?

Answer 121

• Foetal lie (longitudinal, transverse or oblique)
• Presentation (cephalic or breech)
  
  • If cephalic, the degree of engagement must be determined in terms of fifths of the face that are palpable abdominally
• A head that remains high (5/5 palpable) and unengaged (>2/5 palpable) is a poor prognostic sign for vaginal delivery
• If there is any doubt, an ultrasound scan should be performed to identify the reason for the head being high (e.g. placenta praevia, OP position)
• Abdominal examination should include an assessment of the contractions (mainly the strength of contractions, which is not shown on CTG)

Question 122

What should be included in the vaginal examination when managing normal labour?

Answer 122

• The cervix should be examined for position, length and effacement, dilatation and application to the presenting part
• ‘Station’ refers to how far the foetal head has descended into the pelvis
• The length of the cervix at 36 weeks gestation should be around 3 cm - this gradually shortens through the process of effacement
• Dilatation is assessed digitally in centimetres
• At around 4 cm dilated the cervix should be fully effaced
• When no cervix can be felt, it means that the cervix is fully dilated (10 cm)
• Vaginal examination also allows assessment of foetal head position, station, attitude and the presence of caput or moulding
• Normally, the vertex is the presenting point
• The occiput can be identified by feeling the triangular posterior fontanelle with the three suture lines
• Failure to feel the posterior fontanelle may be due to the head being deflexed, the occiput is posterior or there is so much moulding that the sutures cannot be felt
• Normally the occiput is transverse (OT position) or anterior (OA position)
• Assessing the distance between the leading part of the head to the ischial spines will give an estimation of the station
• If the membranes have ruptured, the amount and colour of amniotic fluid draining should be noted (a good amount of clear fluid is good)

Question 123

What care should women with no risk factors following the admission history and examination be managed under?

Answer 123

• Midwifery care

- If there are risk factors, involvement of the on-call obstetric team may be necessary

Question 124

What observations should women in labour have done?

Answer 124

• Pulse measured hourly
• Blood pressure and temperature measured every 4 hours
• Passage of urine should be noted and it should be tested for ketones and protein
• Once the second stage of labour has been entered, blood pressure and pulse should be measured hourly and vaginal examinations should be offered every hour

Question 125

How does hypoxia occur during labour?

Answer 125

• Contractions disrupt placental blood flow and oxygen transfer
• The hypoxia leads to anaerobic respiration, which can result in metabolic acidosis if prolonged and severe
  
  • This can cause neuronal damage
• Hypoxia and acidosis cause a characteristic change in foetal heart rate (FHR) pattern
  
  • This can be detected by auscultation or CTG

Question 126

What is meconium?

When is it excreted?

Answer 126

• Meconium is often passed by a healthy foetus at or after term due to maturation of the GI tract (usually thin and dark green/brown)
  
  • It may also be expelled when a foetus is exposed to marked intrauterine hypoxia or acidosis (thick and brighter green)

Question 127

What are the foetal assessment options in labour?

Answer 127

• Inspection of amniotic fluid
• Intermittent auscultation using a Pinard stethoscope or hand-held Doppler
• Continuous external electronic foetal monitoring (EFM) using CTG
• Continuous internal electronic foetal monitoring (EFM) using foetal scalp electrode (FSE) and CTG
• Foetal scalp blood sampling (FBS)

Question 128

How should FHR be auscultated?

Answer 128

• Using a Pinard stethoscope or by using a hand-held Doppler device
• It should be listened to for at least 1 minute after a contraction
• Repeat every 15 mins during the first stage of labour
• Repeat every 5 mins during the second stage of labour
• EFM (electronic foetal monitoring using CTG) may be used if complications occur

Question 129

What are the indications for continuous EFM?

Answer 129

• Significant meconium staining of the amniotic fluid
• Abnormal FHR detected by intermittent auscultation
• Maternal pyrexia
• Fresh vaginal bleeding
• Augmentation of contractions with oxytocin infusion
• Maternal request

Question 130

Why may the CTG quality be poor?

Answer 130

Due to

• foetal position
• maternal obesity

Question 131

What can overcome poor CTG quality?

Answer 131

• FSE may overcome this issue
• It is fixed onto the foetal scalp and picks up the FHR directly
• It does NOT cause any harm to the foetus but requires a certain degree of cervical dilatation and the membranes must be ruptured

Question 132

What features of a CTG can be looked at?

Answer 132

• Baseline rate
• Variability
• Accelerations
• Deccelerations

Question 133

Describe how you would use “reassuring” and “non-reassuring” to describe CTG

Answer 133

• If all features are reassuring = normal CTG
• If 1 feature is non-reassuring = suspicious CTG
• If 2 or more features are non-reassuring or any one abnormal feature = pathological CTG

Question 134

Due to CTG’s high false positive rate, what can be done to prevent unnecessary intervention?

Answer 134

• Foetal scalp blood sampling (FBS) may be performed during labour to measure foetal pH and base excess

Question 135

What is a partogram?

What are other important observations in labour?

Answer 135

• A graphic record of labour
• Allows instant visual assessment of the progress of labour based on the rate of cervical dilatation compared with an expected norm (according to parity)
• Other important observations include frequency and strength of contractions, descent of the head, station, amount and colour of amniotic fluid draining and basic observations of maternal wellbeing

Question 136

Describe management during the first stage of labour?

Answer 136

• Pain relief when needed
• Adequate hydration and light diet to prevent ketosis (which can impair uterine contractility)
• Women in the latent phase of labour should be encouraged to mobilise and should be managed away from the labour suite
• Intervention should be avoided where possible
• Vaginal examinations performed every 4 hours to determine whether the active phase has been reached (around 4 cm dilatation and full effacement)
• Increase vaginal examinations if the midwife suspects that progress of labour is unusually slow or fast or if there are foetal concerns
• Descent of the presenting part should also be recorded
• During this phase, the membranes may be intact or may have ruptured
• Standing upright may encourage progress of labour (so mobility should be encouraged)
• Antacids should be given to women who have been given opioid analgesia

Question 137

Describe the management during the 2nd stage of labour

Answer 137

• First sign of the second stage is likely to be an urge to push experienced by the mother
• Full dilatation of the cervix should be confirmed by a vaginal examination if the head is not visible
• The woman will get an expulsive reflex with each contraction and will generally take a deep breath, hold it and strain down (Valsalva)
• Women should be discouraged from lying supine or semi-supine
• Maternal and foetal surveillance should intensify
• Use of regional anaesthesia (epidural or spinal) may interfere with the normal urge to push - meaning that the second stage is more often diagnosed on routine scheduled vaginal examination
• In all cases, the baby should be delivered within 4 hours of reaching full dilatation

Question 138

How is descent and delivery of the head managed?

Answer 138

• Can be judged by watching the perineum
• Between contractions, the elastic tone of the perineal muscles will push the head back into the pelvic cavity
• When the head no longer recedes between contractions it is called crowning
• This indicates that delivery is imminent
• As crowning occurs, the hands of the midwife are used to flex the foetal head and guard the perineum
• Once the head has crowned, the woman should be discouraged from bearing down by telling her to take rapid, shallow breaths

Question 139

What is the immediate care of the neonate?

Answer 139

• The baby will usually take its first breath within seconds
• There is no need for immediate clamping
• The baby’s head should be kept dependent to allow mucus in the respiratory tract to drain
• After clamping and cutting the umbilical cord, the baby should have an Apgar score calculated at 1 minute of age and then repeated again at 5 minutes
• Immediate skin-to-skin contact between mother and baby will help bonding and promote the further release of oxytocin which will encourage uterine contractions
• The baby should be dried and covered with a warm blanket or towel
• Initiation of breastfeeding should be encouraged within the first hour of life
• Routine measurements of newborn head circumference, birthweight and temperature should be measure soon after this hour
• The first dose of vitamin K should be given in the delivery room

Question 140

What is considered prolonged in the 3rd stage of labour?

Answer 140

• If > 30 minutes

Question 141

What is the active management of the 3rd stage of labour?

Answer 141

• Recommended to ALL women
• Controlled cord traction
• Reduces postpartum haemorrhage from 15% to 5%
• When the signs of placental separation are recognised, controlled cord traction is used to expedite delivery of the placenta
• When a contraction is felt, the left hand should be moved suprapubically and the fundus elevated with the palm of the hand facing towards the mother
• Uterine inversion is a rare complication
• In 2% of cases, the placenta will not be expelled by this method
• If no bleeding occurs, another attempt should be made after 10 mins
• If this fails, the placenta is ‘retained’ and requires manual removal under general or regional anaesthesia in the theatre
• NOTE: delayed cord clamping from 1-3 minutes may be preferable

Question 142

What is the physiological management of the 3rd stage of labour?

Answer 142

• Placenta is delivered by maternal effort with no uterotonic drugs
• Associated with heavier bleeding
• If haemorrhage occurs or the placenta is undelivered after 60 mins, active management should be recommended

Question 143

What should be inspected after the completion of the 3rd stage of labour?

Answer 143

• After completion of the third stage, the placenta should be inspected for missing cotyledons or a succenturiate lobe
  
  • If suspected, examination under anaesthesia and manual removal of placental tissue (MROP) should be arranged
• Finally, the vulva should be inspected for tears

Question 144

Give a summary of the features of a normal labour

Answer 144

• Spontaneous onset at 37-42 weeks
• Singleton pregnancy
• Cephalic vertex presentation
• No artificial interventions
• Cervical dilatation of at least 1 cm every 2 hours in the active phase of the first stage
• Active second stage no more than 2 hours in primiparous and 60 mins in multiparous women
• Spontaneous vaginal delivery
• Third stage lasting no more than 30 mins with active management

Question 145

What are features of abnormal labour?

Answer 145

• Poor progress (delayed cervical dilatation or descent of presenting part)
• Foetus shows signs of compromise
• Foetal malpresentation
• Multiple pregnancy
• Uterine scar
• Induced labour

Question 146

What are the patterns of abnormal progress in labour?

Answer 146

• Partograms help detect poor progress
• Prolonged Latent Phase
  
  • Latent phase is longer than expected
  • More common in primiparous women
  • Best managed with simple analgesics, mobilisation and reassurance
  • This is very frustrating for the woman
• Primary Arrest
  
  • < 2 cm cervical dilatation per 4 hours in active 1st stage
  • More common in primiparous women
  • Most commonly caused by insufficient uterine contractions
  • Other causes: cephalopelvic disproportion, malposition and malpresentation
• Secondary Arrest
  
  • Occurs when progress in the active first stage is initially good but then slows or stops altogether, usually after 7 cm dilatation
  • May be due to inefficient uterine contractions, malposition, malpresentation and cephalopelvic disproportion
• Arrest in second stage of labour
  
  • Occurs when delivery is NOT imminent after the usual interval of pushing in the second stage of labour
  • May be due to inefficient uterine activity, malposition, malpresentation, CPD or resistant perineum

Question 147

How is poor progress in 1st stage of labour defined?

Answer 147

• Defined as cervical dilatation of less than 2 cm in 4 hours
• Usually associated with failure of descent and rotation of the foetal head
• May be due to any of the 3 Ps: powers, passage, passenger

Question 148

What is Dysfunctional Uterine Activity? (Powers)

Answer 148

• MOST COMMON cause of poor progress in labour
• More common in primigravidae and in older women
• Characterised by weak, irregular and infrequent contractions
• Uterine contractions are usually assessed by carrying out clinical examination and by external uterine tocography
• NOTE: intrauterine pressure catheters are available but are invasive
• 4-5 contractions per 10 mins is ideal
• If contractions are less frequent, more frequent examinations may be required (vaginal examination every 2 hours rather than 4 hours)
• If delay is confirmed, the woman should be offered artificial rupture of membranes (ARM)
• If there is still poor progress after 2 more hours, advice should be sought from an obstetrician about using an oxytocin infusion to augment the contractions
  
  • The infusion is started slowly initially, then increased every 30 mins according to a protocol
  • Continuous EFM is necessary because excessive contractions can cause foetal compromise
  • Women should be offered an epidural before oxytocin is started

Question 149

Are multiparous women more or less likely to experience poor progres due to dysfunctional uterine activity?

Answer 149

• Less likely

Always exclude alternative causes e.g. malposition

Question 150

What may excessive uterine contractions in an obstructed labour result in?

Answer 150

• Uterine rupture

Question 151

What is recommended if progress fails despite 4-6 hours of augmentation with oxytocin?

Answer 151

• Caesarean section

Question 152

What is cephalopelvic distortion?

How may it occur? (Passages and Passenger)

Answer 152

• CPD implies an anatomical disproportion between the foetal head and the maternal pelvis (either due to large head or small pelvis)
• The pelvis may be abnormally small due to previous fracture or metabolic bone disease
• Obstructive hydrocephalus can cause macrocephaly
• Relative CPD is more common and occurs with malposition of the foetal head
• The occipito-posterior position is associated with deflexion of the foetal head, which present a larger skull diameter to the maternal pelvis
• Oxytocin can be given with caution in a primigravida woman with mild to moderate CPD provided that the CTG is normal
• Oxytocin must NEVER be used in a multiparous woman where CPD is suspected

Question 153

What are findings suggestive of CPD?

Answer 153

• Foetal head not engaged
• Progress is slow or arrests despite efficient uterine contractions
• Vaginal examination shows severe moulding and caput formation
• Head is poorly applied to the cervix
• Haematuria

Question 154

Describe malpresentation

Answer 154

• Firm application of the foetal presenting part onto the cervix is necessary for good progress
• A face presentation may apply poorly to the cervix resulting poor progress, but vaginal birth is still possible
• Brow presentation (neck is slightly less extended than in face presentation) is associated with mento-vertical diameter presenting
  
  • This is too large to fit through the bony pelvis unless flexion or hyperextension to a face presentation occurs
  • Brow presentation often manifests as poor progress in the first stage
• Shoulder presentations cannot be delivered vaginally so poor progress will occur
• Malpresentation is more common in women of high parity
• Malpresentation carries a risk of uterine rupture if labour is allowed to continue without progress

Question 155

What are some abnormalities of birth canal?

What is cervical dystocia?

Answer 155

• CPD can delay progress
• Unsuspected fibroids in the lower uterine segment can prevent descent of the foetal head
• Cervical dystocia can also cause delay - this is when the cervix is non-compliant and effaces but fails to dilate because of severe scarring or rigidity (usually due to previous cervical surgery)
• C-section may be necessary

Question 156

From the onset of the second active stage, when should birth take place within?

Answer 156

• 3 hours = nulliparous

- 2 hours = parous

Question 157

How is delay diagnosed? (Poor progress in second stage)

Answer 157

• if delivery is NOT imminent after:
  
  • 2 hours of pushing = nulliparous
  • 1 hour of pushing = parous

Question 158

What is secondary dysfunctional uterine activity?

Answer 158

• A common cause of second stage delay
• This may be exacerbated by epidural analgesia
• After achieving full dilatation, the uterine contractions may become weak
• This is sometimes associated with maternal dehydration and ketosis
• If NO mechanical problem is anticipated and the woman is primiparous, treatment is with rehydration and IV oxytocin
• If the woman is multiparous, a full clinical assessment should be performed by a skilled obstetrician prior to considering oxytocin

Question 159

How does android pelvis cause delay?

Answer 159

• Android pelvis (narrow pelvis) may cause delay in the second stage because it prevent internal rotation of the foetal head
  
  • This may arrest descent of the foetal head at the level of the ischial spines in the transverse position (deep transverse arrest)

Question 160

What can cause second stage delay?

Answer 160

• Android pelvis
• Resistant perineum
• Persistent OP position can also cause delay and would require long rotation to OA or be delivered in OP position (face to pubes)

Question 161

What do the NICE guidelines say by the time second stage delay is diagnosed?

Answer 161

• Oxytocin should not be started

- So, inefficient uterine activity should be corrected at the beginning of the second stage

Question 162

What can be considered for prolonged second stage?

Answer 162

• Instrumental vaginal delivery
• Only if safety criteria are met
• This can be done in the labour room or in the theatre (allowing C-section to be performed easily if needed)

Question 163

What may be indicated if a resistant perineum results in significant delay?

Answer 163

• Episiotomy

Question 164

Summarise the management options of delay in second stage

Answer 164

• Continued pushing with encouragement
• Regular reviews of progress and foetal wellbeing
• Oxytocin to augment contractions
• Episiotomy for a resistant perineum
• Instrumental vaginal birth
• C-section

Question 165

What may foetal compromise present as?

Answer 165

• Fresh meconium staining of the amniotic fluid
• Abnormal CTG
• NOTE: neither confirm foetal hypoxia or acidosis as meconium can be passed for physiological reasons (e.g. maturity) and abnormal CTG carries a high false-positive rate

Question 166

What are the risk factors for foetal compromise in labour?

Answer 166

• Placental insufficiency (FGR and pre-eclampsia)
• Prematurity
• Postmaturity
• Multiple pregnancy
• Prolonged labour
• Augmentation with oxytocin/hyperstimulation
• Precipitate labour
• Intrapartum abruption
• Cord prolapse
• Uterine rupture/dehiscence
• Maternal diabetes
• Cholestasis of pregnancy
• Maternal pyrexia/chorioamnionitis
• Oligohydramnios

Question 167

When is meconium staining significant?

Answer 167

If it is
- Thick or tenacious (clingy)

• Dark green, bright green or black

Question 168

What does thin and light meconium signify?

Answer 168

• Foetal gut maturity

Question 169

If any meconium is seen in liquor, what should be considered?

Answer 169

• Do EFM and CTG

- This is MANDATORY if the meconium is THICK and DARK

Question 170

When should a CTG be started with regards to foetal compromise?

Answer 170

• If there is
  
  • foetal tachycardia, bradycardia or FHR decelerations
• CTG can be classified as normal, suspicious or pathological

Question 171

If the CTG is classified as suspicious or pathological in possible foetal compromise, what should be done?

Answer 171

If the CTG is suspicious

• Repositioning the mother
• IV fluids
• Reducing or stopping oxytocin
• Correction of epidural-associated hypotension
• Continue CTG observation

If the CTG is pathological, consider above factors but also carry out an immediate vaginal examination to exclude malpresentation and cord prolapse and to assess the progress of labour

• If the cervix is fully dilated, instrumental delivery may be possible
• If the cervix is NOT fully dilated, foetal blood sampling may be considered
  
  • If the result is NORMAL, labour can continue but repeat samples may be needed every 30-60 mins if CTG abnormalities persist
• An ABNORMAL result requires immediate C-section if the cervix is not fully dilated

Fresh, thick meconium with a reassuring CTG is still a cause of concern
- `Threshold for intervention should be lower and a paediatrician should be present at delivery

Question 172

Describe resuscitating the foetus in labour

Answer 172

• Maternal dehydration and ketosis
  
  • Give IV fluids
• Maternal hypotension secondary to an epidural
  
  • Reversed by fluid bolus (vasoconstrictor such as ephedrine may occasionally be used)
• Uterine hyperstimulation from excess oxytocin
  
  • Turn off infusion temporarily and use tocolytic drugs (e.g. terbutaline)
• Venocaval compression and reduced uterine blood flow
  
  • Turn woman to left lateral position

Question 173

How is foetal blood sampling done?

Answer 173

• Woman is asked to lie in the left lateral position
• Amnioscope is inserted into the vagina and the end is applied to the foetal head
• The scalp is cleaned and a small cut is made and blood is collected into microtube (about 0.25 mL of blood is required)
• Normal pH = 7.25
  
  • pH < 7.20 is considered foetal compromise
  • pH 7.20-7.25 is borderline

Question 174

What are non-pharmacological methods of pain relief in labour?

Answer 174

• One-to-one care from a midwife can reduce the need for analgesia
• Relaxation and breathing exercises
• NOTE: prolonged hyperventilation can cause alkalosis and dizziness
• Relaxation in warm water during first stage
• Transcutaneous electrical nerve stimulation (TENS)
  
  • Blocks pain fibres in the posterior ganglia of the spinal cord
  • May be used in the latent phase

Question 175

What are pharmacological methods of pain relief in labour?

Answer 175

• Opiates (e.g. pethidine and diamorphine) are used in most obstetric units
• They should be available at all pregnancies but beware of side-effects
• Opiates tend to be given as IM injections
• Alternative route is a subcutaneous or IV infusion by a patient-controlled analgesic device (PCA)
• If a very short-acting opiate is used, the opiate dose can be timed with the contractions

Question 176

What are the side effects of opioid analgesia?

Answer 176

• Nausea and vomiting (should always be given with an antiemetic)
• Maternal drowsiness and sedation
• Delayed gastric emptying (increasing the risks of general anaesthesia)
• Short-term respiratory depression of the baby
• Possible interference with breastfeeding

Question 177

What is inhalational analgesia?

Answer 177

• Nitrous oxide in the form of Entonox (NO and oxygen) is available on most labour wards
• It has a quick onset and short duration of effect
• May cause light-headedness and nausea
• NOT suitable for prolonged use from early labour because hyperventilation can lead to hypocapnia, dizziness and (rarely) foetal hypoxia
• It is most suitable later in labour or whilst awaiting epidural analgesia

Question 178

What is epidural anaesthesia?

What must woman be warned about regarding it?

Answer 178

• MOST RELIABLE means of providing effective analgesia in labour
• The decision to opt for epidural analgesia lies with the woman (unless there are contraindications)
• Warn the woman that:
  
  • She may lose sensation and movement in her legs temporarily
  • IV access and more intensive maternal and foetal monitoring will be necessary (e.g. with continuous EFM)
• Epidural analgesia does NOT increase C-section rates
• It does, however, cause a longer second stage and increases risk of instrumental delivery
• Epidural is not ideal for women in the first stage because it limits mobility

Question 179

What are the indications for epidural anaesthesia?

Answer 179

• Prolonged labour/oxytocin augmentation
• Maternal hypertensive disorders
• Multiple pregnancy
• Selected maternal medical conditions
• A high risk of operative intervention

Question 180

What are the contraindications for epidural anaesthesia?

Answer 180

• Coagulation disorders (e.g. low platelet count)
• Local or systemic sepsis
• Hypovolaemia
• Logistical: insufficient numbers of trained staff (anaesthetic and midwifery)

Question 181

What are the complications of epidural anaesthesia?

Answer 181

• Accidental dural puncture
• Leakage of CSF if the subarachnoid space is reached causing a spinal headache
  
  • If the headache is severe or persistent, a blood patch may be necessary - involves injecting a small volume of the woman’s blood into the epidural space at the level of the accidental dural puncture
• Bladder dysfunction (loss of awareness of needing to micturate)
• Overdistension of the bladder can cause permanent damage and voiding problems
  
  • To avoid this, catheterisation should be carried out during labour if the woman does not void significant volumes of urine spontaneously
• Hypotension
  
  • Treated with IV fluids and vasopressors
• Accidental total spinal anaesthesia (injection of the analgesic into the subarachnoid space)
  
  • Severe hypotension
  • Respiratory failure
  • Unconsciousness
  • Death
• Spinal haematoma
• Drug toxicity
• Short-term respiratory depression of the baby (because epidural solutions contain opioids)

Question 182

Describe the technique for epidural anaesthesia

Answer 182

• Woman’s back is cleansed and local anaesthetic is used to infiltrate the skin
• The woman may be in the left lateral position or sitting upright but leaning over
• Aseptic technique is used
• The epidural catheter is normally inserted at L2-L3, L3-L4 or L4-L5 interspace and should lie in the epidural space
• The catheter is aspirated to check for position and, if no blood or CSF is obtained, a test dose is given to confirm the catheter position
• The test dose is a small volume of dilute local anaesthetic that should not have any clinical effect if applied in the epidural space
• If there is no change in sensation in the lower limbs, then the catheter is in the correct position
• If there is sensory block, leg weakness and peripheral vasodilation, the catheter has been inserted into the subarachnoid space
• If no signs have been observed within 5 mins of the test dose, the loading dose can be administered
• The epidural solution is usually a mixture of low-concentration local anaesthetic (e.g. bupivicane) and an opioid (e.g. fentanyl)
• After the loading dose, the mother should be kept in the right or left lateral position and her blood pressure should be measured every 5 mins for 15 mins
• A fall in blood pressure may be caused by blocking the sympathetic tone to peripheral blood vessels
  
  • This can cause foetal bradycardia
  • Treat with IV fluids and vasoconstrictors (e.g. ephedrine) if necessary
• The woman should NOT lie supine because it can cause aorto-caval compression (compression of the aorta and inferior vena cava but the gravid uterus)
• Hourly assessment of the level of sensory block using a cold spray is critical in the detection of a block that is creeping too high and risking respiratory compromise
• Regional anaesthesia can be maintained through labour with either intermittent boluses or continuous infusions

Question 183

Describe spinal anaesthesia

Answer 183

• A spinal block is more effective than an epidural and has a faster onset
• The needle is inserted through the dura into the subarachnoid space
• They may be used for:
  
  • C-section
  • Trial of instrumental deliveries
  • Manual removal of retained placenta
  • Repair of difficult perineal and vaginal tears
  • Combined spinal-epidural (CSE) analgesia is a viable option for pain relief in labour

Question 184

What are pre-existing uterine scars from?

Answer 184

• Previous C-section

Question 185

Why are 99% of C-sections performed in the lower segment of uterus?

Answer 185

• Because risk of uterine rupture is lower

Question 186

What are the chances of uterine rupture?

Answer 186

• Risk of uterine rupture or dehiscence (scar separation) occurs in 1 in 200 women who labour spontaneously with pre-existing lower segment uterine scar

Question 187

What are signs of uterine rupture?

Answer 187

• Severe lower abdominal pain
• Vaginal bleeding
• Haematuria
• Cessation of contractions
• Maternal tachycardia
• Foetal compromise (often bradycardia)

Question 188

What are the risks of uterine rupture to the mother and foetus?

Answer 188

• Mother: shock, need for blood transfusion, operative repair, hysterectomy
• Foetus: hypoxia, permanent neurological injury and perinatal death

Question 189

When is uterine rupture more likely to occur?

Answer 189

• Late in the first stage of labour with induced or accelerated labour

Question 190

What percentage of women who attempt vaginal birth after caesarean will be successful?

Answer 190

• 70-80% of women who attempt vaginal birth after caesarean (VBAC) will be successful and the remainder will require C-section

Question 191

How should a woman with a history of C-section and is admitted to labour be managed?

Answer 191

• Close surveillance to identify early signs of uterine rupture
• Continuous CTG monitoring is recommended with a low threshold for delivery by C-section

Question 192

What are relative contraindications for VBAC?

Answer 192

• Two or more previous C-section scars
• Need for induction of labour
• Cephalopelvic disproportion in previous labour
• Previous classical C-section is an ABSOLUTE contraindication

Question 193

What are the complications of breech presentation?

Answer 193

• Increased risk of cord prolapse (particularly with footling breech)
• Increased risk of CTG abnormalities as cord compression is common
• Mechanical difficulties with delivery of the shoulders leading to damage to the visceral organs/brachial plexus
• Delay in the delivery of the head leading to prolonged compression of the umbilical cord and asphyxia
• Uncontrolled rapid delivery of the head may occur with a small foetus and predisposes to tentorial tears and intracranial bleeding
• A small or preterm foetus may deliver through an incompletely dilated cervix resulting in head entrapment

Question 194

Describe face presentation and C-section

Answer 194

• Occurs in 1 in 500 labours due to complete extension of the foetal head
• The presenting diameter is the submento-bregmatic which is about 9.5 cm in diameter and has roughly the same dimensions as the suboccipito-bregmatic presentation
• Engagement of the foetal head is late and progress in labour is usually slow
• Diagnosed by palpating the nose, mouth and eyes on vaginal examination
• If there is good progression in labour and the chin remains mento-anterior, vaginal delivery is possible with the head being delivered in flexion
• If the chin is posterior (mento-posterior), delivery is IMPOSSIBLE
  
  • C-section should be performed
  • Oxytocin should NOT be used

Question 195

Describe brow presentation and C-section

Answer 195

• Arises when there is less extreme extension of the foetal neck than with face presentation
• It is a midway position between vertex and face presentation
• It is the LEAST COMMON malpresentation
• The presenting diameter is mento-vertical (13.5 cm) and is incompatible with vaginal delivery
• It is diagnosed by palpating the anterior fontanelle, supraorbital ridges and nose on vaginal examination
• If this position persists, C-section is necessary

Question 196

Describe shoulder presentation and C-section

Answer 196

• Occurs in 1 in 300 pregnancies at term
• Occurs as a result of transverse or oblique lie of the foetus
• This can be caused by:
  
  • Placenta praevia
  • High parity
  • Pelvic tumour
  • Uterine anomaly
• Delivery should be by C-section
• Delay in diagnosing shoulder presentation could result in cord prolapse and uterine rupture

Question 197

Describe multiple pregnancy and C-section

Answer 197

• 1 in 80 pregnancies are multi-foetal
• Incidence is rising due to increasing maternal age and assisted contraception
• High-order multiples tend to be delivered by C-section
• For twin pregnancies, the second twin is at greater risk of intrapartum compromise than the presenting twin
• C-section is not necessarily indicated in twin pregnancies, however they end up being performed in almost half of all twin pregnancies
• In 70-80% of pregnancies the presenting twin is cephalic (the remainder are mainly breech)
• Vaginal delivery is usually achievable if the presenting twin is in a cephalic vertex presentation
• Planned C-section will usually be performed if the first twin is in breech, and almost certainly if it is transverse

Question 198

Describe induction of labour

Answer 198

• This is the planned initiation of labour prior to its spontaneous onset
• 20-25% or deliveries in the UK occur following IOL
• Generally, IOL is performed when the risks to the foetus and/or the mother of the pregnancy continuing outweigh those of bringing the pregnancy to an end
• MOST COMMON reason is prolonged pregnancy (used to be known as post-term or postdates)
• Pregnancies extending beyond 42 weeks are associated with increased risk of stillbirth, foetal compromise in labour, meconium aspiration and mechanical problems at delivery
• So, women are usually offered IOL between 41-42 weeks
• Prelabour rupture of membranes (PROM) is another common indication for IOL
• If there is a long delay between membrane rupture and delivery of the baby, there is a greater risk of ascending infection (chorioamnionitis)
• If beyond 37 weeks, evidence supports use of IOL around 24 hours following membrane rupture
• If < 34 weeks, another additional indication is needed to justify IOL if the membranes rupture (e.g. foetal compromise, growth restriction)
• If 34-37 weeks, in an otherwise straight forward pregnancy, the benefits of IOL need to be assessed on an individual basis
• Pre-eclampsia and other maternal hypertensive disorders often indicate earlier delivery
  
  • If it occurs at term, it is normally managed with IOL
  • If very preterm (< 34 weeks) or if there is rapid foetal or maternal compromise, C-section may be a better option

Question 199

When can IOL happen?

Answer 199

• Prolonged pregnancy (> 41 weeks)
• PROM
• Pre-eclampsia and other maternal hypertensive disorders
• FGR
• Diabetes mellitus
• Deteriorating maternal illness
• Unexplained antepartum haemorrhage
• Twin pregnancy continuing beyond 38 weeks
• Intrahepatic cholestasis of pregnancy
• Maternal isoimmunisation against red cell antigens
• Social reasons

Question 200

What are absolute contraindications to IOL?

Answer 200

• Placenta praevia

- Severe foetal compromise

Question 201

What conditions favour C-section?

Answer 201

• Deteriorating maternal condition
• Major antepartum haemorrhage
• Pre-eclampsia
• Maternal cardiac disease
• Breech (relative contraindication)
• Preterm
  
  • Not an absolute contraindication but induction < 34 weeks is associated with higher risk of failure and the need for C-section

Question 202

What is the Bishops score?

Answer 202

• If labour is induced before cervical changes take place, the labour will take longer
• The Bishop score is used to quantify how far the process of cervical changes has progressed before IOL
• High scores (favourable cervix) are associated with an easier, shorter induction process
• Low scores (unfavourable cervix) is more likely to take longer and more likely to fail and result in C-section

Question 203

What is the method for inducing labour?

Answer 203

• Prostaglandin E2 (PGE2) is the most commonly used formulation
• It is inserted vaginally into the posterior fornix as a tablet or gel
• Two doses are often required, given at least 6 hours apart
• A controlled-released pessary is also available and this is left in place for up to 24 hours
• Labour may ensure following administration of prostaglandins but ARM and oxytocin are often also necessary (particularly in primiparous women)
• Oxytocin is given IV as a dilute solution (as it has a short half-life)
  
  • NOTE: the response to oxytocin is highly variable so strict protocol must be followed
  • The starting infusion rate is low and defined increments will follow every 30 mins until 3-5 contractions are achieved every 10 mins
• Mifepristone (antiprogesterone) and misoprostol (another prostaglandin) can be used to induce labour
• Membrane sweeping describes insertion of a gloved finger through the cervix and its rotation around the inner rim of the cervix
  
  • This strips off the chorionic membrane from the underlying decidua and releases natural prostaglandins
  • It can be uncomfortable and is only possible if the cervix is beginning to dilate and efface
  • It reduces the need for induction
  • Usually only performed at term
  • Placenta praevia must be excluded before it is performed

Question 204

What are complications of inducing labour?

Answer 204

• More pain experienced with induced labour
• Epidural analgesia is more commonly used
• Rates or instrumental delivery are higher when epidural analgesia is used
• NO higher rate of C-section
• Increased risk of PPH secondary to uterine atony
• Uterine hyperstimulation may cause foetal compromise as a side-effect of using prostaglandins and oxytocin
• Contraction frequency of >5 per 10 mins should be treated by stopping oxytocin and, if necessary, administering a tocolytic drug (usually SC injection of terbutaline (beta-2 agonist))
• Uterine hyperstimulation may cause foetal bradycardia and the need for an emergency C-section if FHR fails to resolve promptly
• If ARM is performed when the foetal head is high, cord prolapse can occur which may need a C-section
• The risk of uterine rupture in women with a previous C-section scar who are induced is higher than if they went through spontaneous labour
• IOL failure is said to have occurred if ARM is still impossible after the maximum number of doses of prostaglandin have been given or if the cervix remains uneffaced and < 3 cm dilated after an ARM has been performed and oxytocin has been running for 6-8 hours with regular contractions

Question 205

What are the options if IOL fails?

Answer 205

• Rest then attempt induction again

- C-section

Question 206

What percentage of women who deliver vaginally will have some degree of perineal trauma?

Answer 206

• 85%

Question 207

What percentage of women will need suturing after vaginal birth?

Answer 207

• 60-70%

Question 208

What are risk factors for perineal tears?

Answer 208

• Prolonged labour
• Big babies
• Instrumental delivery
• During active second stage

Question 209

What does external sphincter incompetence lead to?

Answer 209

• Faecal urgency

Question 210

What does internal sphincter incompetence lead to?

Answer 210

• Faecal incontinence

Question 211

What are obstetric anal sphincter injuries? (OASIs)

Answer 211

• Third and fourth degree tears

Question 212

Describe the surgical technique of perineal tear repair

Answer 212

• Adequate analgesia should be provided by topping up an epidural or by infiltration with local anaesthetic
• A pad or tampon to prevent blood loss from the uterus obscuring the view
• Vaginal mucosa is repaired first using rapidly absorbable suture material
• A continuous stitch should be used to close the vaginal mucosa
• Interrupted sutures are placed to close the muscle layer
• Closure of perineal skin is done with either interrupted sutures or a continuous subcuticular stitch
• A gentle vaginal examination should be performed to check for any missed tears and to ensure that good opposition is achieved
• A rectal examination should be performed to confirm that the sphincter feels intact and to ensure that no sutures have been inadvertently placed through the rectal mucosa

Question 213

Describe OASI repair

Answer 213

• Regional or general anaesthetic (to achieve relaxation of the sphincter)
• Repair rectal mucosa
• Repair torn external sphincter
• Some surgeons do an end-to-end repair whereas others prefer an overlap method
• The rest of the perineal repair is as for second-degree trauma

Question 214

Describe OASI aftercare

Answer 214

• Lactulose and a bulking agent (e.g. Fybogel) are recommended for 5-10 days
• Remain in hospital until first bowel motion happens
• An oral broad-spectrum antibiotic should be prescribed for 5-7 days to reduce the risk of infection
• Regular oral analgesia
• At 6-12 weeks, a full evaluation of the degree of symptoms should take place
• Asymptomatic women should be told that the risk in future pregnancy is 6-8% and vaginal delivery is safely achievable

Question 215

What is an episiotomy?

Answer 215

• An episiotomy is a surgical incision of the perineum performed during the second stage of labour to enlarge the vulval outlet and assist vaginal birth
• Episiotomies are used in about 10% of spontaneous vaginal deliveries in the UK (rates vary in other countries)

Question 216

Describe the surgical technique of an episiotomy

Answer 216

• Episiotomy is performed in the second stage when the perineum is being stretched
• If there is NOT a good epidural, the perineum should be infiltrated with local anaesthetic
• If an effective epidural is in place, it should be topped up for delivery with the patient upright to get best coverage of the perineal area
• The incision can be midline or at an angle from the posterior end of the vulva
• A mediolateral episiotomy at a 60 degree angle to midline is usually recommended
• The midline episiotomy results in less bleeding, quicker healing and less pain but there is an increased risk of extension to involve the anal sphincter (OASI)
• The episiotomy should be repaired in the same way as a second-degree tear unless involvement of the anal sphincter requires OASI repair

Question 217

What are the complications of an episiotomy?

Answer 217

• Pain
• Infection
• Haemorrhage
• Dyspareunia
• Incontinence of urine
• Incontinence of flatus or faeces
• Risks are highest with OASI

Question 218

What is an operative vaginal delivery?

Answer 218

• Refers to vaginal birth with the use of any type of forceps or vacuum extractor (ventouse)
• The goal is to speed up delivery with a minimum of maternal and neonatal morbidity
• 10-15% of deliveries in the UK are assisted with instruments
• The rate is higher in nulliparous women (around 30%)

Question 219

What is the most common foetal factor for an OVD?

Answer 219

• Suspected foetal compromise is the MOST COMMON foetal factor
• It is based on an pathological CTG

Question 220

What is the most common maternal factor for an OVD?

Answer 220

• Prolonged active second stage of labour

Question 221

Describe some contraindications of OVD?

Answer 221

• If the safety criteria is NOT met, OVD is contraindicated
• NOT to be used if < 34 weeks because of high risk of cephalhaematoma and intracranial haemorrhage
• NOT used for face or breech presentation
• Minimal risk of haemorrhage if a vacuum extractor is used following foetal blood sampling or foetal scalp electrode
• Forceps or vacuum extractor delivery is contraindicated before full dilatation of the cervix

Question 222

What are the pros of using a ventouse for OVD?

Answer 222

• Lower risk of pelvic floor trauma with ventouse
• Lower risk of anal sphincter injury with ventouse
• Higher risk of lacerations and facial palsy with forceps
• Less likely to need maternal regional or general anaesthesia
• Less likely to cause significant perineal pain at 24 hours
• No difference in pelvic floor symptoms 5 years after instrumental delivery between forceps and ventouse
• Both are associated with low 5 minute Apgar scores

Question 223

What are the pros of using forceps for OVD?

Answer 223

• Lower failure rate than Ventouse for vaginal delivery
• Lower risk of cephalohaematoma and cerebral haemorrhage than ventouse
• Lower risk of retinal haemorrhage than ventouse
• No difference in pelvic floor symptoms 5 years after instrumental delivery between forceps and ventouse
• Both are associated with low 5 minute Apgar scores

Question 224

How does C-section compare to instrumental delivery?

Answer 224

• Women who deliver by C-section more likely to have a major haemorrhage and to need a hospital stay for more than 5 days
• Babies delivered by C-section were less likely to have trauma than babies delivered by forceps but were more likely to require intensive care
• Women who had a C-section are much more likely to require a C-section in future pregnancies

Question 225

Describe the evaluation of OVD

Answer 225

• Thorough vaginal and abdominal examination should take place to confirm the foetal lie, presentation, engagement, station, position, attitude and degree of caput or moulding
• This will confirm whether the basic safety criteria for OVD have been met
• Anthropoid (narrow), android (male/funnel-shaped) or platypelloid (elliptical) pelvises make instrumental delivereis MORE difficult
• A trial push is helpful to determine whether descent is possible and allows attempted correction of malposition

Question 226

Describe analgesia use in OVD

Answer 226

• More analgesia is required for forceps compared to ventouse
• Forceps - regional anaesthesia is preferred
• Rigid cup ventouse - pudendal block with perineal infiltration
• Soft cup ventouse - perineal infiltration with local anaesthetic

Question 227

What is the positioning for OVD?

Answer 227

• Classically performed with patients in the lithotomy position
• The bladder should be emptied

Question 228

What is the contingency plans for OVD?

Answer 228

• A failed vacuum delivery may be completed with low-pelvic forceps
• But a failed or abandoned forceps delivery will almost always result in C-section
• The risk of shoulder dystocia and postpartum haemorrhage should always be considered

Question 229

Describe the technique of Ventouse delivery

Answer 229

• Soft cups are more likely to fail than rigid cups
• However, soft cups cause less scalp injury
• Soft cups are suitable for uncomplicated deliveries with an OA position
• Metal cups are better for OP, transverse and difficult OA position
• For successful use of the ventouse, determination of the flexion point is vital
• This is at the vertex, which is on the saggital suture 3 cm anterior to the posterior fontanelle and 6 cm posterior to the anterior fontanelle
• The centre of the cup should be positioned directly over this
• Operating suction pressure is 0.6-0.8 kg/cm2
• Check that no maternal tissue is caught under the edge
• Traction must along in the plane of least resistance along the axis of the pelvis (usually at exactly 90 degrees to the cup)
• Operator should keep a thumb and forefinger on the cup and foetal scalp to ensure traction direction is correct and to feel for slippage
• Safe and gentle traction is applied and coordinated with uterine contractions and maternal expulsive efforts
• The descent phase brings the head onto the perineum
• The crowning phase occurs shortly afterwards
• Rotation is achieved through the natural passage of the head through the pelvis
• The operator should not allow any more than 2 episodes of the suction popping off during delivery
• The maximum time from application to delivery should be < 15 mins

Question 230

What are the different types of forceps?

Answer 230

• Blades may be fenestrated, pseudofenestrated or solid
• Length of shanks and design of the lock vary between models
• Non-rotational forceps are used when the head is OA with no more than 45 degrees deviation to the left or right
• Examples of non-rotational forceps
  
  • Neville Barnes
  • Simpson
• If the head is positioned > 45 degrees from the vertical, rotation must be accomplished before tractions
• Examples of rotational forceps
  
  • Kielland

Question 231

Describe the technique of forceps delivery

Answer 231

• The left blade is usually inserted before the right with the operators hand protecting the vaginal wall from the blades
• The forceps blades will end up lying parallel to the axis of the foetal head
• The operator will then lock the blades
• Traction should be applied intermittently coordinated with uterine contractions and maternal expulsive efforts
• The axis of traction changes during delivery and is guided along the J-shaped curve of the pelvis
• As the head crowns, the blades are directed to the vertical and the head is delivered
• Most forceps deliveries will be completed with no more than three pulls
• In practice, most obstetricians cut an episiotomy routinely for forceps delivery
• This is more likely in nulliparous women

Question 232

What are complications of OVD?

Answer 232

• Maternal deaths have been reported with vacuum deliveries as a result of cervical tearing in women delivered before full dilatation
• Faecal incontinence
• Postpartum haemorrhage
• Underestimation of blood loss
• Cephalhaematoma (ventouse)
• Risk of trauma to the baby correlates with duration of operative vaginal delivery and difficulty of the delivery

Question 233

What is a C-section?

Answer 233

• A C-section is a surgical procedure where incisions are made through a woman’s abdomen (laparotomy) and uterus (hysterotomy) to deliver one or more babies
• 25-30% of all babies in the UK are delivered by C-section

Question 234

What are four major indications for a C-section?

Answer 234

• Previous C-section
• Malpresentation (mainly breech)
• Failure to progress in labour
• Suspected foetal compromise

Question 235

What are other indications for a C-section?

Answer 235

• Multiple pregnancy
• Placental abruption
• Placenta praevia
• Foetal disease
• Maternal disease

Question 236

What is tocophobia?

Answer 236

• Irrational fear of childbirth
• It is important to distinguish mothers who request C-section because they want to avoid labour from those that want to avoid it because of a previous traumatic birth experience

Question 237

What is the procedure for a C-section?

Answer 237

• Informed consent
• Preparation
• Abdominal incision
• Uterine incision
• Closure

Question 238

Describe informed consent in a C-section

Answer 238

• Must be obtained before surgery

- Potential indications should be discussed in the antenatal period

Question 239

Describe the preparation for a C-section

Answer 239

• Most scheduled C-sections are performed under spinal anaesthesia with the mother awake
• If an epidural has been placed during labour there is usually enough time to top-up the anaesthesia before emergency C-section
• General anaesthesia is occasionally required
• Bladder should be emptied before the procedure and a urinary catheter is usually kept in situ
• A left lateral tilt minimises aorto-caval compression and reduces the incidence of hypotension and reduced placental perfusion
• The anaesthetic block is confirmed and the woman’s abdomen is cleaned and draped
• Prophylactic antibiotics should be administered IV before the surgical incision

Question 240

Describe the abdominal incision for a C-section

Answer 240

• The skin and subcutaneous tissues are incised using either a transverse curvilinear incision 2 finger breadths above the symphysis pubis extending from and to points lateral of the lateral margins of the abdominal rectus muscles (Pfannenstiel incision)
• An alternative incision is a transverse suprapubic incision with no curve
• Subcutaneous tissues are separated by blunt dissection and the rectus sheath is incised transversely along the middle 2 cm
• The incision is extended with scissors before the fascial sheath is separated form the underlying muscle by blunt dissection
• The recti are separated, the peritoneum incised and the abdominal cavity entered
• A vertical incision is used in cases of extreme maternal obesity, suspicion of other intra-abdominal pathology or where access to the uterine fundus is required
  
  • The vertical incision allows easy access to the pelvic and intra-abdominal organs but there is an increased incidence of wound dehiscence (splitting open)

Question 241

Describe the uterine incision for a C-section

Answer 241

• A lower uterine segment transverse incision is used in >95% of C-section deliveries due to ease of repair, reduced blood loss and low incidence of dehiscence or rupture in subsequent pregnancies
• The classical C-section incision incorporates the upper uterine segment with a vertical incision - this has few absolute indications but include:
  
  • Lower uterine segment obscured by fibroids
  • Lower segment covered with dense adhesions
  • Placenta praevia
  • Transverse lie with the back down
  • Foetal abnormality (e.g. conjoined twins)
  • C-section in the presence of carcinoma of the cervix
• Once the uterus is incised, the membranes are ruptured if still intact and the operator’s hand is placed below the presenting part
• If cephalic, the head is flexed and delivered by elevation through the uterine incision either manually or with forceps
• Fundal pressure is applied by the assistant to aid delivery
• Once the foetus is delivered, an oxytocic agent (5 IU syntocinon IV) is administered to aid uterine contraction and placental separation
• The placenta is delivered by controlled cord traction

Question 242

Describe the closure of a C-section

Answer 242

• Closure should be performed in either single or double layers with continuous or interrupted sutures
• A running stitch is usually employed
• A second layer is commonly used to improve haemostasis and the integrity of the scar
• Peritoneal closure is NOT routine and depends on the operator’s preference
• Abdominal closure is performed in the anatomical planes
• The skin can be closed by absorbable or non-absorbable suture material or with clips

Question 243

What are general complications of a C-section?

Answer 243

• Haemorrhage
• Infections of the wound
• Urinary tract infection
• Infection of the endometrium
• Transient tachypnoea of the newborn
• Fatality from C-section is 5 x that of vaginal delivery (but this is mainly because of emergency C-section)

Question 244

What are intraoperative complications of a C-section?

Answer 244

• Haemorrhage
  
  • May be due to damage to uterine vessels
  • May occur as a consequence of uterine atony or placenta praevia
  • In patients with an anticipated high risk of haemorrhage (e.g. placenta praevia), blood should be routinely cross-matched
• Caesarean Hysterectomy
  
  • The most common indication is uncontrollable maternal haemorrhage
  • Life-threatening haemorrhage occurs in about 1 in 1000 deliveries
  • The most important risk factor for emergency postpartum hysterectomy is a previous C-section
    
    • This is especially bad if the placenta overlies the old scar –> increased risk of placenta accreta
  • Other indications for hysterectomy:
    
    • Atony
    • Uterine rupture
    • Extension of a transverse uterine incision
    • Fibroids preventing uterine closure and haemostasis
• Placenta praevia
  
  • Risk of placenta praevia increases with each previous C-section
  • So, future reproductive intensions are important when considering C-section
• Organ damage
  
  • Bowel damage may occur during a repeat procedure if adhesions are present from a previous surgery
• Bladder injury
• Damage to ureters

Question 245

What are postoperative complications of a C-section?

Answer 245

• Infection
  
  • C-section has a 5-20 fold increased risk of infectious complications compared to vaginal delivery
  • Fever
  • Wound infection
  • Endometritis
  • Bacteraemia
  • UTI
  • Other causes of post-operative fever: haematoma, atelectasis, DVT
  • The duration of labour and the presence of ruptured membranes seem to be the biggest risk factors
  • Infections are often polymicrobial and include E. coli, aerobic Gram-negative rods and group B streptococcus
  • Prophylactic antibiotics reduce the risk of infection
• Venous Thromboembolism
  
  • C-section is a major risk factor
  • Incidence can be reduced by:
    
    • Adequate hydration
    • Early mobilisation
    • Prophylactic heparin
• Psychological
  
  • Delayed contact with the baby can contribute to psychological distress

Question 246

Describe subsequent delivery following C-section

Answer 246

• Up to 70% of women with a previous C-section who labour achieve vaginal delivery
• Two options for women with previous C-section:
  
  • Elective repeat caesarean section (ERCS)
  • Attempted vaginal birth after caesarean section (VBAC)
• If the first operation was carried out for a non-recurrent indication, and providing the obstetric situation close to term in the subsequent pregnancy is favourable, then it is appropriate to offer a trial of labour after caesarean (TOLAC) to any woman with a previous uncomplicated lower segment C-section

Question 247

What are the benefits of ERCS to the mother?

Answer 247

• Avoid pelvic floor trauma (urinary and faecal problems)
• Avoid the need to undergo emergency C-section
• Avoid scar dehiscence or rupture

Question 248

What are the risks of ERCS?

Answer 248

• Increased bleeding
• Febrile morbidity
• Prolonged recovery
• Thromboembolism
• Long-term bladder dysfunction
• Increased risk of placenta praevia in subsequent pregnancies