Labour and Delivery Flashcards
Prophylaxis of preterm labour
- Vaginal progesterone
- Cervical cerclage (stitch in cervix)
Diagnosis of preterm prelabour rupture of membranes
- Speculum examination (amniotic fluid pooling in the vagina)
If doubt:
* Insulin-like growth factor-binding protein-1 (IGFBP-1) is a protein present in high concentrations in amniotic fluid
* Placental alpha-microglobin-1 (PAMG-1) is a similar alternative to IGFBP-1
Management of preterm prelabour rupture of membranes
- Prophylactic antibiotics (to prevent chorioamnionitis) - erythromycin 250mg QDS 10 days
- Induction of labour (from 34 weeks)
Define preterm prelabour rupture of membranes
Preterm prelabour rupture of membranes is where the amniotic sac ruptures, releasing amniotic fluid, before the onset of labour and in a preterm pregnancy (under 37 weeks gestation)
What is preterm labour with intact membranes
Preterm labour with intact membranes = involves regular painful contraction + cervical dilation - without the rupture of the amniotic sac
How is preterm labour with intact membranes diagnosed?
Speculum examination to assess cervical dilatation
- Less than 30 weeks gestation: Clinical assessment alone IS enough to offer management of preterm labour
- More than 30 weeks gestation: transvaginal ultrasound to assess cervical length (less than 15mm - management is offered; more than 15mm - preterm labour is unlikely)
Fetal firbonectin = alternative to vaginal USS
Fetal fibronectin is the “glue” between the chorion and the uterus, and is found in the vagina during labour. A result of less than 50 ng/ml is considered negative, and indicates that preterm labour is unlikely.
Management of preterm labour with intact membranes
- Fetal monitoring (CTG or intermittent auscultation)
- Tocolysis with nifedipine: nifedipine is a calcium channel blocker that suppresses labour
- Maternal corticosteroids: can be offered before 35 weeks gestation to reduce neonatal morbidity and mortality
- IV magnesium sulphate: can be given before 34 weeks gestation and helps protect the baby’s brain
- Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby at birth
What is tocolysis and which medication is used?
Tocolysis = medications to stop uterine contractions
* Nifedipine = calcium channel blcoker
* Atosiban = oxytocin receptor antagonist (alternative to nifedipine)
Tocolysis = used between 24 and 33+6 weeks gestation in preterm labour - to delay delivery + buy time for future fetal development + administration of maternal steroids
Used as short term measure (less than 48 hours)
Why are antenatal steroids given and when?
Giving the mother corticosteroids = helps develop the fetal lungs → reduce respiratory distress syndrome after delivery
Used in women with suspected preterm labour of babies less than 36 weeks gestation
E.g. 2 doses of intramuscular betamethasone (24 hours apart)
Why is IV magnesium sulfate given during premature delivery ?
- Giving the mother IV magnesium sulfate = helps to protect the fetal brain during preterm delivery
- Reduces risk + severity of cerebral palsy
- Magnesium sulfate = given within 24 hours of delivery of delivery of preterm babies of less than 34 weeks of gestation
Mothers need close monitoring for magnesium toxicity at least four hourly. This involves close monitoring of observations, as well as tendon reflexes (usually patella reflex). Key signs of toxicity are:
- Reduced respiratory rate
- Reduced blood pressure
- Absent reflexes
IV magnesium sulfate = given as bous - followed by an infusion for up to 24 hours or until birth
Indications for an elective cesarean section
- Previous caesarean
- Symptomatic after a previous significant perineal tear
- Placenta praevia
- Vasa praevia
- Breech presentation
- Multiple pregnancy
- Uncontrolled HIV infection
- Cervical cancer
What anaesthetic is used for an elective C-section?
Spinal anaesthetic
Injection of a local anaesthetic (such as lidocaine) into the cerebrospinal fluid at the lower back. This blocks the nerves from the abdomen downwards.
When in gestation is an elective c-section performed?
From 39 weeks if possible
The 4 categories of an emergency caesarean section
- Category 1: There is an immediate threat to the life of the mother or baby. Decision to delivery time is 30 minutes.
- Category 2: There is not an imminent threat to life, but caesarean is required urgently due to compromise of the mother or baby. Decision to delivery time is 75 minutes.
- Category 3: Delivery is required, but mother and baby are stable.
- Category 4: This is an elective caesarean, as described above.
What is the most commonly used skin incision in an caesarean section?
Transverse lower uterine segment incision
The two possible incisions in a caesarean section
- Pfannenstiel incision is a curved incision two fingers width above the pubic symphysis
- Joel-cohen incision is a straight incision that is slightly higher (this is the recommended incision)
When is a vertical incision used in a caesarean section?
- Very premature deliveries
- Anterior placenta praevia
Layers of the abdomen that need to be dissected during a caesarean section
- Skin
- Subcutaneous tissue
- Fascia / rectus sheath (the aponeurosis of the transversus abdominis and external and internal oblique muscles)
- Rectus abdominis muscles (separated vertically)
- Peritoneum
- Vesicouterine peritoneum (and bladder) – the bladder is separated from the uterus with a bladder flap
- Uterus (perimetrium, myometrium and endometrium)
- Amniotic sac
The baby is delivered by hand with the assistance of pressure on the fundus. Forceps may be used if necessary.
The uterus is closed inside the abdomen using two layers of sutures. Exteriorisation (taking the uterus out of the abdomen) is avoided if possible. The abdomen and skin are then closed.
Risks of anaesthetic
- Allergic reactions or anaphylaxis
- Hypotension
- Headache
- Urinary retention
- Nerve damage (spinal anaesthetic)
- Haematoma (spinal anaesthetic)
- Sore throat (general anaesthetic)
- Damage to the teeth or mouth (general anaesthetic)
Measures to reduce the risk of complications during a caesarian section
- H2 receptor antagonists (e.g. ranitidine) or proton pump inhibitors (e.g. omeprazole) before the procedure
- Prophylactic antibiotics during the procedure to reduce the risk of infection
- Oxytocin during the procedure to reduce the risk of postpartum haemorrhage
- Venous thromboembolism (VTE) prophylaxis with low molecular weight heparin
Why is oxytocin given during an caesarean section?
Reduce the risk of a postpartum haemorrhage
Why are PPIs (e.g. omeprazole) or H2 receptor antagonists (e.g. ranitidine) given before a caesarean section?
To reduce the risk of aspiration pneumonitis during the c-section - caused by acid reflux + aspiration during the prolonged period of lying down
Risks of c-section, what are the….:
- General surgical risks
- Damage to local structures
General surgical risks:
- Bleeding
- Infection
- Pain
- Venous thromboembolism
Damage to local structures:
- Ureter
- Bladder
- Bowel
- Blood vessels
What are some complications in the postpartum period that can occur after a c-section?
- Post-partum haemorrhage
- Wound infection
- Wound dehiscence
- Endometritis
Name 3 effects on the adbominal organs that can occur as a result of a c-section
- Ileus
- Adhesions
- Hernias
What are the:
- Effects on future pregnancies
- Effects on the baby
As a result of a c-section?
Effects on future pregnancies:
* Increased risk of repeat caesarean
* Increased risk of uterine rupture
* Increased risk of placenta praevia
* Increased risk of stillbirth
Effects on the baby:
* Risk of lacerations (about 2%)
* Increased incidence of transient tachypnoea of the newborn
Can you have a vaginal birth after a caesarean section?
Yes!
**Vaginal birth after caesarean (VBAC) **
* Success rate = 75%
* Uterine rupture risk 0.5%
Contraindications for a VBAC
- Previous uterine rupture
- Classical caesarean scar (a vertical incision)
- Other usual contraindications to vaginal delivery (e.g. placenta praevia)
Having a caesarean section is likely to lead to a period of reduced mobility. Women should have a VTE risk assessment performed to determine the type and duration of VTE prophylaxis (follow local guidelines).
Prophylaxis for VTE involves….
- Early mobilisation
- Anti-embolism stockings or intermittent pneumatic compression of the legs
- Low molecular weight heparin (e.g. enoxaparin)
Define postpartum haemorrhage
Bleeding after the delivery of baby + placenta
Postpartum haemorrhage = most common cause of obstetric haemorrhage, potential cause of maternal death
To be classified as postpartum haemorrhage, there needs to be a loss of:
- 500ml after a vaginal delivery
- 1000ml after a caesarean section
Categories of postpartum haemorrhage
- Minor PPH – under 1000ml blood loss
- Major PPH – over 1000ml blood loss
Major PPH can be further sub-classified as:
- Moderate PPH – 1000 – 2000ml blood loss
- Severe PPH – over 2000ml blood loss
It can also be categorised as:
Primary PPH: bleeding within 24 hours of birth
Secondary PPH: from 24 hours to 12 weeks after birth
Lisa loses 1500ml of blood after delivering the placenta and baby, what is the calssification of PPH?
Moderate PPH (major)
4 causes of postpartum haemorrhage
4 Ts
* T – Tone (uterine atony – the most common cause)
* T – Trauma (e.g. perineal tear)
* T – Tissue (retained placenta)
* T – Thrombin (bleeding disorder)
Risk factors for a PPH
- Previous PPH
- Multiple pregnancy
- Obesity
- Large baby
- Failure to progress in the second stage of labour
- Prolonged third stage
- Pre-eclampsia
- Placenta accreta
- Retained placenta
- Instrumental delivery
- General anaesthesia
- Episiotomy or perineal tear
Name some preventative measures for postpartum haemorrhages
- Treating anaemia during the antenatal period
- Giving birth with an empty bladder (a full bladder reduces uterine contraction)
- Active management of the third stage (with intramuscular oxytocin in the third stage)
- Intravenous tranexamic acid can be used during caesarean section (in the third stage) in higher-risk patients
Management for a postpartum haemorrhage
- Resuscitation with an ABCDE approach
- Lie the woman flat, keep her warm and communicate with her and the partner
- Insert two large-bore cannulas
- Bloods for FBC, U&E and clotting screen
- Group and cross match 4 units
- **Warmed IV fluid and blood resuscitation **as required
- Oxygen (regardless of saturations)
- Fresh frozen plasma is used where there are clotting abnormalities or after 4 units of blood transfusion
In severe cases, activate the major haemorrhage protocol. Each hospital will have a major haemorrhage protocol, which gives rapid access to 4 units of crossmatched or O negative blood.
What are the categories of treatment to stop the bleeding in a PPH?
- Mechanical
- Medical
- Surgical
What is the mechanical treatment options for a PPH?
- Rubbing the uterus through the abdomen to stimulates a uterine contraction (referred to as “rubbing up the fundus”)
- Catheterisation (bladder distention prevents uterus contractions)
What is the medical treatment options for a PPH?
- Oxytocin (slow injection followed by continuous infusion)
- Ergometrine (intravenous or intramuscular) stimulates smooth muscle contraction (contraindicated in hypertension)
- Carboprost (intramuscular) is a prostaglandin analogue and stimulates uterine contraction (caution in asthma)
- Misoprostol (sublingual) is also a prostaglandin analogue and stimulates uterine contraction
- Tranexamic acid (intravenous) is an antifibrinolytic that reduces bleeding
TOM TIP: The intravenous infusion of oxytocin is given as 40 units in 500 mls. You may hear midwives or obstetricians referring only to “40 units” without specifying the drug. They are referring to an oxytocin infusion for PPH.
What is the surgical treatment options for a PPH?
- Intrauterine balloon tamponade – inserting an inflatable balloon into the uterus to press against the bleeding
- B-Lynch suture – putting a suture around the uterus to compress it
- Uterine artery ligation – ligation of one or more of the arteries supplying the uterus to reduce the blood flow
- Hysterectomy is the “last resort” but will stop the bleeding and may save the woman’s life
What does ergometrine do?
(Why useful in PPH)
Stimulates smooth muscle contraction
Ergometrin = contraindicated in hypertension
Why is carboprost used in a PPH?
Carboprost = prostaglandin analogue - stimulates uterine contraction
Caution in asthma
What does misoprostol do?
Why useful in PPH?
Misoprostol = prostaglandin analogue
Stimulates uterine contraction
What is tranexamic acid and why is it useful in PPH?
Tranexamic acid = antifibrinolytic
Reduces bleeding
What is most likely to cause a secondary postpartum haemorrhage?
- Retained products of conception (RPOC)
- Infection (e.g. endometritis)
Ix and Mx for postpartum haemorrhage
Ix:
* Ultrasound - for RPOC
* Endocervical + high vaginal swabs - for infection
Mx:
* Surgical evaluation - of RPOC
* Antibiotics for infection
What antibiotic is used after an instrumental delivery to reduce the risk of maternal infection?
Single dose of co-amoxiclav
What are the indications for an instrumental delivery?
- Failure to progress
- Fetal distress
- Maternal exhaustion
- Control of the head in various fetal positions
It is worth remembering there is an increased risk of requiring an instrumental delivery when an epidural is in place for analgesia.
What are the risks to the mother in an instrumental delivery?
- Postpartum haemorrhage
- Episiotomy
- Perineal tears
- Injury to the anal sphincter
- Incontinence of the bladder or bowel
- Nerve injury (obturator or femoral nerve)
What are the risks to the baby in an instrumental delivery?
- Cephalohaematoma with ventouse
- Facial nerve palsy with forceps
What is the main complication for a baby with a ventouse delivery?
Cephalohaematoma
(Collection of blood between the skull and the periosteum)
What is the main complication with a forceps delivery?
Facial nerve palsy - with facial paralysis on one side
May cause bruises
Rarely fat necrosis on cheeks (hardened lumps of fat) - resolves spontaneously
What are the 2 main nerve injuries that can occur due to an instrumental delivery?
- Femoral nerve → weakness of knee extension, loss of patella reflex, numbess of anterior thigh + medial lower leg
- Obtrurator nerve → weakness of hip adduction, numbness of medial thigh
What is uterine rupture?
Uterine rupture = complication of labour
The myometrium = ruptures
Info: Uterine rupture and layers involved
- Incomplete rupture (or uterine dehiscence) → perimetrium (uterine serosa) = remains intact
- Complete rupture → perimetrium + myometrium = ruptures → uterus contents = released into the peritoneal cavity
Incomplete rupture → myometrium = ruptures
Complete rupture → myometrium + perimetrium = ruptures
What in uterine rupture leads to a high morbidity + mortality for the baby and mother?
- Significant bleeding
- The baby may be released from the uterus into the peritoneal cavity
What are the major risk factors for uterine rupture?
PREVIOUS CAESAREAN SECTION - the scar becomes a point of weakness → may rupture with excessive pressure (e.g. excessive stimulation by oxytocin)
Other risk factors:
* Vaginal birth after caesarean (VBAC)
* Previous uterine surgery
* Increased BMI
* High parity
* Increased age
* Induction of labour
* Use of oxytocin to stimulate contractions
How does uterine rupture present?
Acutely unwell mother + abnormal CTG
It may occur with induction or augmentations of labour - with signs and symptoms of:
- CEASING OF UTERINE CONTRACTIONS
- Abdominal pain
- Vaginal bleeding
- Hypotension
- Tachycardia
- Collapse
Management of uterine rupture
Uterine rupture = obstetric emergency
* Resuscitation + transfusion
* Emergency c-section → remove baby
* Stop any bleeding, repair, remove (hysterectomy) uterus
Define the ‘lie’
Lie = the relationship between the long axis of the fetus and the mother
- Longitudinal
- Transverse
- Oblique
Define ‘presentation’
Presentation = the fetal part that first enters the maternal pelvis
- Cephalic vertex presentation = the most common and is considered the safest
- Other presentations include breech, shoulder, face and brow
Define ‘position’
Position = the position of the fetal head as it exits the birth canal
- Usually the fetal head engages in the occipito-anterior position (the fetal occiput facing anteriorly) – this is ideal for birth
- Other positions include occipito-posterior and occipito-transverse.
What is the most common malpresentation?
Breech
Name some risk factors for abnormal lie, malpresentation and malposition
- Prematurity
- Multiple pregnancy
- Uterine abnormalities (e.g fibroids, partial septate uterus)
- Fetal abnormalities
- Placenta praevia
- Primiparity
How are fetal lie and presentation identified?
Via abdominal examination
How is the fetal position identified?
Vaginal examination
How can any suspected abnormal fetal lie or malpresentation be confirmed?
Ultrasound scan
(This could also demonstrate predisposing uterine or fetal abnormalities)
What can be attempted if fetal lie is abnormal?
External cephalic version (ECV)
(Ideally between 36 and 38 weeks gestation)
What is external cephalic version (ECV)?
ECV = manipulation of the fetus to a cephalic presentation through the maternal abdomen
Success rate: 50% in primiparous women and 60% in multiparous wome
Only 8% of breech presentations will spontaneously revert to cephalic in primiparous women over 36 weeks gestation.
Complications (= rare):
* Fetal distress
* Premature rupture of membranes
* Antepartum haemorrhage (APH)
* Placental abruption
Contraindications:
* Recent APH
* Recent ruptured membrane
* Uterine abnormalities
* Previous C-section
Management of malpresentations
Breech: attempt ECV before labour, vaginal breech delivery or C-section
Brow: C-section is necessary
Face:
* If the chin is anterior (mento-anterior) a normal labour is possible; however, it is likely to be prolonged and there is an increased risk of a C-section being required
* If the chin is posterior (mento-posterior) then a C-section is necessary
Shoulder: C-section is necessary
Info: Malposition
- 90% of malpositions spontaneously rotate to occipito-anterior as labour progresses.
- If the fetal head does not rotate, rotation and operative vaginal delivery can be attempted. Alternatively a C-section can be performed.
What is cephalopelvic disproportion (CPD)?
Cepalopelvic disproportion (CPD) = where the fetal head is too large to pass through the maternal pelvis → leading to difficulties during childbirth
- CPD = can result in prolonged or obstructed labour
- CPD = significant cause of maternal and neonatal morbidity and requires careful management to ensure the safety of both mother and baby.
Name some causes of cephalopelvic disproportion (CPD)
Fetal:
* Macrosomia: A baby that is larger than average, often due to maternal diabetes.
* Hydrocephalus: An abnormal accumulation of cerebrospinal fluid in the baby’s brain, leading to an enlarged head.
* Malpresentation: The fetal head is not in the optimal position for delivery, such as in breech presentation.
Maternal:
* Pelvic Abnormalities: A small or abnormally shaped pelvis (e.g., android or platypelloid pelvis).
* Previous Pelvic Trauma: Previous injuries or fractures that have altered the shape of the pelvis.
* Maternal Short Stature: Often associated with a smaller pelvis.
* Uterine Abnormalities: Conditions like fibroids that may distort the uterine cavity and affect the fetal position.
Combination factors:
* Disproportionate Growth: A situation where the baby grows disproportionately large relative to the maternal pelvis.
Investigations for cephalopelvic disproportion (CPD)?
CPD = primarily a clinical diagnosis made during labor - when there is a lack of progress despite adequate contractions.
However, certain investigations and assessments can be helpful:
* Vaginal examination: to estimate whether the pelvis can accomodate the fetal head
* Ultrasound: Used to estimate fetal size, presentation, and position. It’s particularly useful in identifying macrosomia or other fetal abnormalities that may contribute to CPD.
* Fetal monitoring: Continuous monitoring of fetal heart rate during labor to detect any signs of fetal distress, which may suggest CPD
Management of cephalopevic disproportion
- Trial of labour (where CPD is suspected but not confirmed. Close monitoring of labor progress and fetal wellbeing is essential.
- Cesarean section
- Assisted vaginal delivery
- Induction of labour
What is postpartum endometritis caused by?
Labour and delivery
The process of delivery opens the uterus to allow bacteria from the vagina to travel upwards and infect the endometrium.
When endometritis occurs unrelated to pregnancy and delivery, it is usually part of pelvic inflammatory disease
Is postpartum endometritis more commonly caused by caesarean sections or vaginal births?
Caesarean section
(Prophylactic antibiotics are given to reduce the risk of infection)
What are the causitive organisms of postpartum endometritis?
Basically everything:
* Gram-neg bacteria
* Gram-positive bacteria
* STIs (chlamydia and gonorrhoea)
Clinical features of postpartum endometritis
Postpartum endometritis can present from shortly after birth to several weeks postpartum. It can present with:
- Foul-smelling discharge or lochia
- Bleeding that gets heavier or does not improve with time
- Lower abdominal or pelvic pain
- Fever
- Sepsis
Investigations for postpartum endometritis
- Vaginal swabs (including chlamydia and gonorrhoea if there are risk factors)
- Urine culture + sensitivities
- Abdominal ultrasound (may be considered to rule out retained products of conception (although it is not used to diagnose endometritis))
Septic patients (hospital admission + septic six)
* Blood cultures
* Broad-spectrum IV antibiotics (clindamycin + gentamicin)
* Blood tests (signs of infection raised WBC + CRP)
Patients presenting with milder symptoms and no signs of sepsis may be treated in the community with oral antibiotics - Co-amoxiclav
Sepsis 6 - BUFALO
* Blood cultures
* Urine output
* Fluids IV
* Antibiotics IV
* Lactate
* Oxygen
