Obstetrics Flashcards
Abdominal pain in pregnancy
Abdominal pain in pregnancy may be divided into causes which occur early, late or at any point.
Early pregnancy
Cause
Notes
Ectopic pregnancy
This is the single most important cause of abdominal pain to exclude in early pregnancy
0.5% of all pregnancies are ectopic
Risk factors (anything slowing the ovum’s passage to the uterus)
damage to tubes (salpingitis, surgery)
previous ectopic
IVF (3% of pregnancies are ectopic)
A typical history is a female with a history of 6-8 weeks amenorrhoea who presents with lower abdominal pain and later develops vaginal bleeding
lower abdominal pain: typically the first symptom. Pain is usually constant and may be unilateral. Due to tubal spasm
vaginal bleeding: usually less than a normal period, may be dark brown in colour
history of recent amenorrhoea: typically 6-8 weeks from start of last period; if longer (e.g. 10 wks) this suggest another causes e.g. inevitable abortion
peritoneal bleeding can cause shoulder tip pain and pain on defecation / urination
Miscarriage
Threatened miscarriage
painless vaginal bleeding occurring before 24 weeks, but typically occurs at 6 - 9 weeks
cervical os is closed
complicates up to 25% of all pregnancies
Missed (delayed) miscarriage
a gestational sac which contains a dead fetus before 20 weeks without the symptoms of expulsion
mother may have light vaginal bleeding / discharge and the symptoms of pregnancy which disappear
when the gestational sac is > 25 mm and no embryonic/fetal part can be seen it is sometimes described as a ‘blighted ovum’ or ‘anembryonic pregnancy’
Inevitable miscarriage
cervical os is open
heavy bleeding with clots and pain
Incomplete miscarriage
not all products of conception have been expelled
Late pregnancy
Cause
Notes
Labour
Regular tightening of the abdomen which may be painful in the later stages
Placental abruption
Placental abruption describes separation of a normally sited placenta from the uterine wall, resulting in maternal haemorrhage into the intervening space
Occurs in approximately 1/200 pregnancies
Clinical features
shock out of keeping with visible loss
pain constant
tender, tense uterus
normal lie and presentation
fetal heart: absent/distressed
coagulation problems
beware pre-eclampsia, DIC, anuria
Symphysis pubis dysfunction
Ligament laxity increases in response to hormonal changes of pregnancy
Pain over the pubic symphysis with radiation to the groins and the medial aspects of the thighs. A waddling gait may be seen
Pre-eclampsia/HELLP syndrome
Associated with hypertension, proteinuria. Patients with HELLP also have haemolysis, elevated liver enzymes and a low platelet count.
The pain is typically epigastric or in the RUQ
Uterine rupture
Ruptures usually occur during labour but occur in third trimester
Risk factors: previous caesarean section
Presents with maternal shock, abdominal pain and vaginal bleeding to varying degree
Any point in pregnancy
Cause
Notes
Appendicitis
Occurs in 1:1,000-2:1,000 pregnancies, making it the most common non-obstetric surgical emergency
Higher morbidity and mortality in pregnancy
Location of pain changes depending on gestation, moving up from the RLQ in the first trimester to the umbilicus in the second and the RUQ in the third
Urinary tract infection (UTI)
1 in 25 women develop in UTI in pregnancy
Associated with an increased risk of pre-term delivery and IUGR
Antenatal care: timetable
NICE issued guidelines on routine care for the healthy pregnant woman in March 2008. They recommend:
10 antenatal visits in the first pregnancy if uncomplicated
7 antenatal visits in subsequent pregnancies if uncomplicated
women do not need to be seen by a consultant if the pregnancy is uncomplicated
Gestation
Purpose of visit
8 - 12 weeks (ideally < 10 weeks)
Booking visit
general information e.g. diet, alcohol, smoking, folic acid, vitamin D, antenatal classes
BP, urine dipstick, check BMI
Booking bloods/urine
FBC, blood group, rhesus status, red cell alloantibodies, haemoglobinopathies
hepatitis B, syphilis, rubella
HIV test is offered to all women
urine culture to detect asymptomatic bacteriuria
10 - 13+6 weeks
Early scan to confirm dates, exclude multiple pregnancy
11 - 13+6 weeks
Down’s syndrome screening including nuchal scan
16 weeks
Information on the anomaly and the blood results. If Hb < 11 g/dl consider iron
Routine care: BP and urine dipstick
18 - 20+6 weeks
Anomaly scan
25 weeks (only if primip)
Routine care: BP, urine dipstick, symphysis-fundal height (SFH)
28 weeks
Routine care: BP, urine dipstick, SFH
Second screen for anaemia and atypical red cell alloantibodies. If Hb < 10.5 g/dl consider iron
First dose of anti-D prophylaxis to rhesus negative women
31 weeks (only if primip)
Routine care as above
34 weeks
Routine care as above
Second dose of anti-D prophylaxis to rhesus negative women*
Information on labour and birth plan
36 weeks
Routine care as above
Check presentation - offer external cephalic version if indicated
Information on breast feeding, vitamin K, ‘baby-blues’
38 weeks
Routine care as above
40 weeks (only if primip)
Routine care as above
Discussion about options for prolonged pregnancy
41 weeks
Routine care as above
Discuss labour plans and possibility of induction
*the evidence base suggests that there is little difference in the efficacy of single-dose (at 28 weeks) and double-dose regimes (at 28 & 34 weeks). For this reason the RCOG in 2011 advised that either regime could be used ‘depending on local factors’
For each of the following components of routine antenatal care select the gestation when it should occur
Antenatal care: specific points
NICE issued guidelines on routine care for the healthy pregnant woman in March 2008
Nausea and vomiting
natural remedies - ginger and acupuncture on the ‘p6’ point (by the wrist) are recommended by NICE
antihistamines should be used first-line (BNF suggests promethazine as first-line)
Vitamin D
NICE recommend ‘All women should be informed at the booking appointment about the importance for their own and their baby’s health of maintaining adequate vitamin D stores during pregnancy and whilst breastfeeding’
‘women may choose to take 10 micrograms of vitamin D per day, as found in the Healthy Start multivitamin supplement’. This was confirmed in 2012 when the Chief Medical Officer advised: ‘All pregnant and breastfeeding women should take a daily supplement containing 10micrograms of vitamin D, to ensure the mothers requirements for vitamin D are met and to build adequate fetal stores for early infancy’
particular care should be taken with women at risk (e.g. Asian, obese, poor diet)
Alcohol
in 2016 the Chief Medical Officer proposed new guidelines in relation to the safe consumption of alcohol following an expert group report.
the government now recommend pregnant women should not drink. The wording of the official advice is ‘If you are pregnant or planning a pregnancy, the safest approach is not to drink alcohol at all, to keep risks to your baby to a minimum. Drinking in pregnancy can lead to long-term harm to the baby, with the more you drink the greater the risk.’
Bleeding in pregnancy
The table below outlines the major causes of bleeding during pregnancy. Antepartum haemorrhage is defined as bleeding after 24 weeks
1st trimester
Spontaneous abortion
Ectopic pregnancy
Hydatidiform mole
2nd trimester
Spontaneous abortion
Hydatidiform mole
Placental abruption
3rd trimester
Bloody show
Placental abruption
Placenta praevia
Vasa praevia
Alongside the pregnancy related causes, conditions such as sexually transmitted infections and cervical polyps should be excluded.
The table below outlines the key features of each condition:
Spontaneous abortion
Threatened miscarriage - painless vaginal bleeding typically around 6-9 weeks
Missed (delayed) miscarriage - light vaginal bleeding and symptoms of pregnancy disappear
Inevitable miscarriage - complete or incomplete depending or whether all fetal and placental tissue has been expelled. Incomplete miscarriage - heavy bleeding and crampy, lower abdo pain. Complete miscarriage - little bleeding
Ectopic pregnancy
Typically history of 6-8 weeks amenorrhoea with lower abdominal pain (usually unilateral) initially and vaginal bleeding later. Shoulder tip pain and cervical excitation may be present
Hydatidiform mole
Typically bleeding in first or early second trimester associated with exaggerated symptoms of pregnancy e.g. hyperemesis. The uterus may be large for dates and serum hCG is very high
Placental abruption
Constant lower abdominal pain and, woman may be more shocked than is expected by visible blood loss. Tender, tense uterus* with normal lie and presentation. Fetal heart may be distressed
Placental praevia
Vaginal bleeding, no pain. Non-tender uterus* but lie and presentation may be abnormal
Vasa praevia
Rupture of membranes followed immediately by vaginal bleeding. Fetal bradycardia is classically seen
*vaginal examination should not be performed in primary care for suspected antepartum haemorrhage - women with placenta praevia may haemorrhage
Chorioamnionitis
Chorioamnionitis (which can affect up to 5% of all pregnancies) is a potentially life-threatening condition to both mother and foetus and is therefore considered a medical emergency. It is usually the result of an ascending bacterial infection of the amniotic fluid / membranes / placenta. The major risk factor in this scenario is the preterm premature rupture of membranes (however, it can still occur when the membranes are still intact) which expose the normally sterile environment of the uterus to potential pathogens. Prompt delivery of the foetus (via cesarean section if necessary) and administration of intravenous antibiotics is widely considered the mainstay of initial treatment for this condition.
Breastfeeding problems
‘Minor’ breastfeeding problems
frequent feeding in a breastfed infant is not alone a sign of low milk supply
nipple pain: may be caused by a poor latch
blocked duct (‘milk bleb’): causes nipple pain when breastfeeding. Breastfeeding should continue. Advice should be sought regarding the positioning of the baby. Breast massage may also be tried
nipple candidiasis: treatment for nipple candidiasis whilst breastfeeding should involve miconazole cream for the mother and nystatin suspension for the baby
Mastitis
Mastitis affects around 1 in 10 breastfeeding women. The BNF advises to treat ‘if systemically unwell, if nipple fissure present, if symptoms do not improve after 12-24 hours of effective milk removal of if culture indicates infection’. The first-line antibiotic is flucloxacillin for 10-14 days. Breastfeeding or expressing should continue during treatment.
If left untreated, mastitis may develop into a breast abscess. This generally requires incision and drainage.
Engorgement
Breast engorgement is one of the causes of breast pain in breastfeeding women. It usually occurs in the first few days after the infant is born and almost always affects both breasts. The pain or discomfort is typically worse just before a feed. Milk tends to not flow well from an engorged breast and the infant may find it difficult to attach and suckle. Fever may be present but usually settles within 24 hours. The breasts may appear red. Complications include blocked milk ducts, mastitis and difficulties with breastfeeding and, subsequently, milk supply.
Although it may initially be painful, hand expression of milk may help relieve the discomfort of engorgement.
Raynaud’s disease of the nipple
In Raynaud’s disease of the nipple, pain is often intermittent and present during and immediately after feeding. Blanching of the nipple may be followed by cyanosis and/or erythema. Nipple pain resolves when nipples return to normal colour.
Options of treatment for Raynaud’s disease of the nipple include advice on minimising exposure to cold, use of heat packs following a breastfeed, avoiding caffeine and stopping smoking. If symptoms persist consider specialist referral for a trial of oral nifedipine (off-license).
Breastfeeding: contraindications
The major breastfeeding contraindications tested in exams relate to drugs (see below). Other contraindications of note include:
galactosaemia
viral infections - this is controversial with respect to HIV in the developing world. This is because there is such an increased infant mortality and morbidity associated with bottle feeding that some doctors think the benefits outweigh the risk of HIV transmission
Drug contraindications
The following drugs can be given to mothers who are breastfeeding:
antibiotics: penicillins, cephalosporins, trimethoprim
endocrine: glucocorticoids (avoid high doses), levothyroxine*
epilepsy: sodium valproate, carbamazepine
asthma: salbutamol, theophyllines
psychiatric drugs: tricyclic antidepressants, antipsychotics**
hypertension: beta-blockers, hydralazine
anticoagulants: warfarin, heparin,
digoxin
The following drugs should be avoided:
antibiotics: ciprofloxacin, tetracycline, chloramphenicol, sulphonamides
psychiatric drugs: lithium, benzodiazepines
aspirin
carbimazole
methotrexate
sulfonylureas
cytotoxic drugs
amiodarone
*the BNF advises that the amount is too small to affect neonatal hypothyroidism screening
**clozapine should be avoided
Breech presentation
In a breech presentation the caudal end of the fetus occupies the lower segment. Whilst around 25% of pregnancies at 28 weeks are breech it only occurs in 3% of babies near term. A frank breech is the most common presentation with the hips flexed and knees fully extended. A footling breech, where one or both feet come first with the bottom at a higher position, is rare but carries a higher perinatal morbidity
Risk factors for breech presentation
uterine malformations, fibroids
placenta praevia
polyhydramnios or oligohydramnios
fetal abnormality (e.g. CNS malformation, chromosomal disorders)
prematurity (due to increased incidence earlier in gestation)
Cord prolapse is more common in breech presentations
Management
if < 36 weeks: many fetuses will turn spontaneously
if still breech at 36 weeks NICE recommend external cephalic version (ECV)- this has a success rate of around 60%. The RCOG recommend ECV should be offered from 36 weeks in nulliparous women and from 37 weeks in multiparous women
if the baby is still breech then delivery options include planned caesarean section or vaginal delivery
Information to help decision making - the RCOG recommend:
‘Women should be informed that planned caesarean section carries a reduced perinatal mortality and early neonatal morbidity for babies with a breech presentation at term compared with planned vaginal birth.’
‘Women should be informed that there is no evidence that the long term health of babies with a breech presentation delivered at term is influenced by how the baby is born.’
RCOG absolute contraindications to ECV:
where caesarean delivery is required
antepartum haemorrhage within the last 7 days
abnormal cardiotocography
major uterine anomaly
ruptured membranes
multiple pregnancy
Chickenpox exposure in pregnancy
Chickenpox is caused by primary infection with varicella-zoster virus. Shingles is caused by the reactivation of dormant virus in dorsal root ganglion. In pregnancy, there is a risk to both the mother and also the fetus, a syndrome now termed fetal varicella syndrome
Risks to the mother
5 times greater risk of pneumonitis
Fetal varicella syndrome (FVS)
risk of FVS following maternal varicella exposure is around 1% if occurs before 20 weeks gestation
studies have shown a very small number of cases occurring between 20-28 weeks gestation and none following 28 weeks
features of FVS include skin scarring, eye defects (microphthalmia), limb hypoplasia, microcephaly and learning disabilities
Other risks to the fetus
shingles in infancy: 1-2% risk if maternal exposure in the second or third trimester
severe neonatal varicella: if the mother develops rash between 5 days before and 2 days after birth there is a risk of neonatal varicella, which may be fatal to the newborn child in around 20% of cases
Management of chickenpox exposure
if there is any doubt about the mother previously having chickenpox maternal blood should be urgently checked for varicella antibodies
if the pregnant women is not immune to varicella she should be given varicella-zoster immunoglobulin (VZIG) as soon as possible. RCOG and Greenbook guidelines suggest VZIG is effective up to 10 days post exposure
consensus guidelines suggest oral aciclovir should be given if pregnant women with chickenpox present within 24 hours of onset of the rash
When contact occurs with chickenpox or shingles, it is paramount to take a detailed clinical history to confirm the significance of the contact and susceptibility of the patient.
Significant contact is defined as face-to-face contact, being in the same room for more than 15 minutes or contact in the setting of a large open ward.
The susceptibility of the woman should be determined by eliciting a past medical history of chickenpox or shingles. If there is a definite past medical history of chickenpox, it is reasonable to assume that she is immune to the varicella infection and no further action is required.
If there is no clear history of previous chickenpox, or she is from a tropical or subtropical area then serological testing for varicella-zoster virus IgG would be required.
Individuals born or raised in tropical climates are less likely to be immune to varicella and a history of chickenpox can be a less reliable predictor of immunity within this population.
RCOG Greentop guidelines, Chickenpox in pregnancy.
Eclampsia
Eclampsia may be defined as the development of seizures in association pre-eclampsia. To recap, pre-eclampsia is defined as:
condition seen after 20 weeks gestation
pregnancy-induced hypertension
proteinuria
Magnesium sulphate is used to both prevent seizures in patients with severe pre-eclampsia and treat seizures once they develop. Guidelines on its use suggest the following:
should be given once a decision to deliver has been made
in eclampsia an IV bolus of 4g over 5-10 minutes should be given followed by an infusion of 1g / hour
urine output, reflexes, respiratory rate and oxygen saturations should be monitored during treatment
respiratory depression can occur: calcium gluconate is the first-line treatment for magnesium sulphate induced respiratory depression
treatment should continue for 24 hours after last seizure or delivery (around 40% of seizures occur post-partum)
Other important aspects of treating severe pre-eclampsia/eclampsia include fluid restriction to avoid the potentially serious consequences of fluid overload
Epilepsy pregnancy and breast feeding
The risks of uncontrolled epilepsy during pregnancy generally outweigh the risks of medication to the fetus. All women thinking about becoming pregnant should be advised to take folic acid 5mg per day well before pregnancy to minimise the risk of neural tube defects. Around 1-2% of newborns born to non-epileptic mothers have congenital defects. This rises to 3-4% if the mother takes antiepileptic medication.
Other points
aim for monotherapy
there is no indication to monitor antiepileptic drug levels
sodium valproate: associated with neural tube defects
carbamazepine: often considered the least teratogenic of the older antiepileptics
phenytoin: associated with cleft palate
lamotrigine: studies to date suggest the rate of congenital malformations may be low. The dose of lamotrigine may need to be increased in pregnancy
Breast feeding is generally considered safe for mothers taking antiepileptics with the possible exception of the barbiturates
It is advised that pregnant women taking phenytoin are given vitamin K in the last month of pregnancy to prevent clotting disorders in the newborn
Sodium valproate
The November 2013 issue of the Drug Safety Update also carried a warning about new evidence showing a significant risk of neurodevelopmental delay in children following maternal use of sodium valproate.
The update concludes that sodium valproate should not be used during pregnancy and in women of childbearing age unless clearly necessary. Women of childbearing age should not start treatment without specialist neurological or psychiatric advice.
Breast feeding is acceptable with nearly all anti-epileptic drugs
Importance: 99
The BNF states ‘breast-feeding is acceptable with all antiepileptic drugs, taken in normal doses, with the possible exception of barbiturates’
Anti-epileptics in pregnancy can be a tricky subject. Many are known to cause severe congenital defects (both structural and intellectual) and as such the first line of care is good contraceptive advice and planning with the patient in question. This is however, not always possible and there will always be cases where a patient becomes pregnant whilst on anti-epileptic medication prior to consulting with a doctor.
The recent MBRRACE-UK and the NICE clinical guidelines both state that most women with epilepsy and of child bearing age are currently prescribed lamotrigine and during pregnancy this may require a dose increase. Phenytoin, phenobarbitone and sodium valproate are all known to have an adverse effect on cognitive abilities and therefore are usually avoided unless absolutely necessary.
Lamotrigine, carbamazepine and levetiracetam are known to have the smallest effects on the developing foetus, however all epileptics who are either pregnant or are planning to become pregnant should be referred to specialist care as soon as possible.
Folic acid
Folic acid is converted to tetrahydrofolate (THF). Green, leafy vegetables are a good source of folic acid.
Functions
THF plays a key role in the transfer of 1-carbon units (e.g. methyl, methylene, and formyl groups) to the essential substrates involved in the synthesis of DNA & RNA
Causes of folic acid deficiency:
phenytoin
methotrexate
pregnancy
alcohol excess
Consequences of folic acid deficiency:
macrocytic, megaloblastic anaemia
neural tube defects
Prevention of neural tube defects (NTD) during pregnancy:
all women should take 400mcg of folic acid until the 12th week of pregnancy
women at higher risk of conceiving a child with a NTD should take 5mg of folic acid from before conception until the 12th week of pregnancy
women are considered higher risk if any of the following apply:
→ either partner has a NTD, they have had a previous pregnancy affected by a NTD, or they have a family history of a NTD
→ the woman is taking antiepileptic drugs or has coeliac disease, diabetes, or thalassaemia trait.
→ the woman is obese (defined as a body mass index [BMI] of 30 kg/m2 or more).
Folic acid is important to prevent neural tube defects in the foetus. Currently it is recommended that all women who are planning to become pregnant should take a supplement of 400 micrograms of folic acid per day whilst trying to conceive and once pregnancy, they should continue taking this dose until the 12th week of pregnancy.
In cases where there has been a previous pregnancy affected by neural tube defects or if there is a family history, this dose should be increased to 5 milligrams, however in the case of this patient there is no history and therefore 400 micrograms is recommended.
Women are advised to take folic acid 400mcg when trying to conceive through to 12 weeks gestation to reduce the incidence of neural tube defects. A higher dose of 5mg is indicated if there are additional risk factors eg. diabetes or personal or family history of neural tube defects. A daily supplement of vitamin D 10mcg is also advised throughout pregnancy for bone health, and should be continued for the duration of breastfeeding. If a woman chooses to take a multivitamin in pregnancy, she should be advised to ensure it does not contain vitamin A (retinol) as it is teratogenic in high doses.
Source: NHS Choices
http://www.nhs.uk/conditions/pregnancy-and-baby/pages/vitamins-minerals-supplements-pregnant.aspx#close
Gestational trophoblastic disorders
Describes a spectrum of disorders originating from the placental trophoblast:
complete hydatidiform mole
partial hydatidiform mole
choriocarcinoma
Complete hydatidiform mole
Benign tumour of trophoblastic material. Occurs when an empty egg is fertilized by a single sperm that then duplicates its own DNA, hence the all 46 chromosomes are of paternal origin
Features
bleeding in first or early second trimester
exaggerated symptoms of pregnancy e.g. hyperemesis
uterus large for dates
very high serum levels of human chorionic gonadotropin (hCG)
hypertension and hyperthyroidism* may be seen
Management
urgent referral to specialist centre - evacuation of the uterus is performed
effective contraception is recommended to avoid pregnancy in the next 12 months
Around 2-3% go on to develop choriocarcinoma
In a partial mole a normal haploid egg may be fertilized by two sperms, or by one sperm with duplication of the paternal chromosomes. Therefore the DNA is both maternal and paternal in origin. Usually triploid - e.g. 69 XXX or 69 XXY. Fetal parts may be seen
*hCG can mimic thyroid-stimulating hormone (TSH)
Group B Streptococcus
GBS is a vaginal commensal isolated in many women. It is known to be the most frequent cause of severe early-onset infection in the newborn and can cause significant morbidity and mortality.
If it is isolated during the antenatal period, it does not require treatment immediately, as it will not reduce the likelihood of colonisation at delivery.
However, intrapartum intravenous benzylpenicillin is required to reduce neonatal transmission. An alternative would be clindamycin. This applies to GBS isolated in vaginal swabs and urine. (GBS urinary tract infection in pregnancy requires appropriate antibiotics at the time also).
There is no screening programme in the UK for GBS, vaginal swabs should be taken only when clinically indicted. Women who have had a previous baby infected with GBS are also offered intrapartum intravenous benzylpenicillin in future pregnancies.
Group B Streptococcus (GBS) is the most common cause of early-onset severe infection in the neonatal period. It is thought around 20-40% of mothers have GBS present in their bowel flora and may therefore be thought of as ‘carriers’ of GBS. Infants may be exposed to maternal GBS during labour and subsequently develop potentially serious infections.
Risk factors for Group B Streptococcus (GBS) infection:
prematurity
prolonged rupture of the membranes
previous sibling GBS infection
maternal pyrexia e.g. secondary to chorioamnionitis
Management
The Royal College of Obstetricians and Gynaecologists (RCOG) published guidelines on GBS in 2017.
The main points are as follows:
universal screening for GBS should not be offered to all women
the guidelines also state a maternal request is not an indication for screening
women who’ve had GBS detected in a previous pregnancy should be informed that their risk of maternal GBS carriage in this pregnancy is 50%. They should be offered maternal intravenous antibiotic prophylaxis (IAP) OR testing in late pregnancy and then antibiotics if still positive
if women are to have swabs for GBS this should be offered at 35-37 weeks or 3-5 weeks prior to the anticipated delivery date
maternal intravenous antibiotic prophylaxis should be offered to women with a previous baby with early- or late-onset GBS disease
maternal intravenous antibiotic prophylaxis should be offered to women in preterm labour regardless of their GBS status
women with a pyrexia during labour (>38ºC) should also be given intravenous antibiotics
benzylpenicillin is the antibiotic of choice for GBS prophylaxis
Group B streptococcus (GBS) bacteriuria is associated with an increased risk of chorioamnionitis and neonatal sepsis. The Royal College of Obstetricians and Gynaecologists states that women with GBS bacteriuria should therefore be offered intrapartum antibiotics in addition to appropriate treatment at the time of diagnosis. For non-penicillin-allergic patients intrapartum antibiotics will consist of intravenous benzylpenicillin given as soon as possible after the start of labour, then at 4-hourly intervals until delivery.
Postnatal antibiotic treatment is not indicated unless there are signs of neonatal infection. Caesarean section is not indicated.
HIV and pregnancy
With the increased incidence of HIV infection amongst the heterosexual population there are an increasing number of HIV positive women giving birth in the UK. In London the incidence may be as high as 0.4% of pregnant women. The aim of treating HIV positive women during pregnancy is to minimise harm to both the mother and fetus, and to reduce the chance of vertical transmission.
Guidelines regularly change on this subject and most recent guidelines can be found using the links provided.
Factors which reduce vertical transmission (from 25-30% to 2%)
maternal antiretroviral therapy
mode of delivery (caesarean section)
neonatal antiretroviral therapy
infant feeding (bottle feeding)
Screening
NICE guidelines recommend offering HIV screening to all pregnant women
Antiretroviral therapy
all pregnant women should be offered antiretroviral therapy regardless of whether they were taking it previously
Mode of delivery
vaginal delivery is recommended if viral load is less than 50 copies/ml at 36 weeks, otherwise caesarian section is recommended
a zidovudine infusion should be started four hours before beginning the caesarean section
Neonatal antiretroviral therapy
zidovudine is usually administered orally to the neonate if maternal viral load is <50 copies/ml. Otherwise triple ART should be used. Therapy should be continued for 4-6 weeks.
Infant feeding
In the UK all HIV positive women should be advised not to breastfeed
In the UK all HIV positive women should be advised not to breastfeed, hence only option 2 is correct. It is not advisable to breastfeed regardless of the viral load, the amount of breastfeeding or whether she or the baby is on the antiretroviral therapy.
Hypertension in pregnancy
NICE published guidance in 2010 on the management of hypertension in pregnancy. They also made recommendations on reducing the risk of hypertensive disorders developing in the first place. Women who are at high risk of developing pre-eclampsia should take aspirin 75mg od from 12 weeks until the birth of the baby. High risk groups include:
hypertensive disease during previous pregnancies
chronic kidney disease
autoimmune disorders such as SLE or antiphospholipid syndrome
type 1 or 2 diabetes mellitus
The classification of hypertension in pregnancy is complicated and varies. Remember, in normal pregnancy:
blood pressure usually falls in the first trimester (particularly the diastolic), and continues to fall until 20-24 weeks
after this time the blood pressure usually increases to pre-pregnancy levels by term
Hypertension in pregnancy in usually defined as:
systolic > 140 mmHg or diastolic > 90 mmHg
or an increase above booking readings of > 30 mmHg systolic or > 15 mmHg diastolic
After establishing that the patient is hypertensive they should be categorised into one of the following groups
Pre-existing hypertension
Pregnancy-induced hypertension
(PIH, also known as gestational hypertension)
Pre-eclampsia
A history of hypertension before pregnancy or an elevated blood pressure > 140/90 mmHg before 20 weeks gestation
No proteinuria, no oedema
Occurs in 3-5% of pregnancies and is more common in older women
Hypertension (as defined above) occurring in the second half of pregnancy (i.e. after 20 weeks)
No proteinuria, no oedema
Occurs in around 5-7% of pregnancies
Resolves following birth (typically after one month). Women with PIH are at increased risk of future pre-eclampsia or hypertension later in life
Pregnancy-induced hypertension in association with proteinuria (> 0.3g / 24 hours)
Oedema may occur but is now less commonly used as a criteria
Occurs in around 5% of pregnancies
The following question tests the understanding of secondary prevention of women with pre-eclampsia. There is A level data showing that low-dose aspirin started at 12-14 weeks’ gestation is more effective than placebo at reducing occurrence of pre-eclampsia in women at high risk, reducing perinatal mortality and reducing the risk of babies being born small for gestational age . There is some evidence that low molecular weight heparin might reduce the placental insufficiency seen in pre-eclampsia, but long-term safety studies are not yet available. Labetalol and methyldopa are both common antihypertensive drugs used in the acute management of pre-eclampsia, however are not given prophylactically and do not reduce intrauterine growth retardation. Similarly to LMWH, unfractionated heparin has not been proven to prevent the development uteroplacental insufficiency.
Even though the patient is asymptomatic, she has a raised blood pressure above 160/100 mmHg combined with the significant proteinuria. Furthermore, this is despite receiving labetalol treatment. She will need emergency admission for monitoring and management of the hypertension in a controlled environment, with delivery being an option if there is no improvement.
Calcium channel blockers and ACE inhibitors, including ramipril, are teratogenic. The most widely used anti-hypertensive for pregnant women is labetalol. NICE recommend labetalol as first-line treatment in moderate and severe gestational hypertension rather than methyldopa. NICE CG107
This patient is suffering from pre-eclampsia. The National Institute for Health and Care Excellence state that women with severe hypertension in pregnancy (160/110mmHg or higher) should be treated with labetalol as first time treatment. Delivery should not be offered to women before 34 weeks unless:
severe hypertension remains refractory to treatment
maternal or fetal indications develop as specified in the consultant plan
At 34 weeks delivery should be offered to women with pre-eclampsia once a course of corticosteroids has been completed.
Intravenous magnesium sulphate can be used in the critical care setting when a woman who has severe hypertension or severe pre-eclampsia has previously had an eclamptic fit. It is not used to solely lower blood pressure.
Frusemide should not be used to treat hypertension in pregnancy because placental perfusion may be reduced and it crosses the placental barrier.
Reference:
NICE: Hypertension in pregnancy: The management of hypertensive disorders during pregnancy. https://www.nice.org.uk/guidance/cg107/chapter/1-Guidance#medical-management-of-severe-hypertension-or-severe-pre-eclampsia-in-a-critical-care-setting
The first line medication for hypertension in pregnancy is labetalol. Methyldopa can also be used but this is not recommended as first line as it is associated with an increased likelihood of postnatal depression.
Ramipril, irbesartan and bendroflumethiazide are teratogenic and therefore should not be given in pregnancy.
Intrahepatic cholestasis of pregnancy
Intrahepatic cholestasis of pregnancy
BreastfeedingObstetric cholestasis, also known as intrahepatic cholestasis of pregnancy, is a condition caused by the impaired flow of bile. This, in turn, causes a build-up of bile salts which can then deposit in the skin (causing pruritus) as well as the placenta. It is thought that the aetiology of this condition is a combination of hormonal, genetic and environmental factors.
Although the pruritic symptoms can be distressing for the mother, the build of bile salts can also be detrimental to foetal well-being. The combination of the immature foetal liver’s ability to cope with breaking down the excessive bile salt levels as well as the vasoconstricting effect of bile salts on human placental chorionic veins, has been theorised to be the cause of sudden asphyxial events in the foetus leading to anoxia and death.
Intrahepatic cholestasis of pregnancy (also known as obstetric cholestasis) affects around 1% of pregnancies in the UK. It is associated with an increased risk of premature birth.
Features
pruritus - may be intense - typical worse palms, soles and abdomen
clinically detectable jaundice occurs in around 20% of patients
raised bilirubin is seen in > 90% of cases
Management
induction of labour at 37 weeks is common practice but may not be evidence based
ursodeoxycholic acid - again widely used but evidence base not clear
vitamin K supplementation
Placenta praevia
Placenta praevia refers to a pathological positioning of the placenta in the lower segment of the uterus, either wholly or partly. If the placenta overlies the internal cervical os then this is classed as ‘major praevia’, whereas in ‘minor’ or ‘partial’ praevia it does not. Bleeding from the placenta can occur spontaneously, as a result of trauma, or at the onset of labour as the cervix opens.
Guidelines issued by the Royal College of Obstetricians and Gynaecologists state that placenta praevia should be considered in all cases of vaginal bleeding occurring after 20 weeks gestation. Features that increase suspicion of this condition include painless bleeding, high presenting part and abnormal fetal lie. Definitive diagnosis generally requires ultrasound examination to identify the position of the placenta.
(RCOG Green-top Guideline No. 27)
With respect to the above case, the absence of pain makes placental abruption very unlikely, and the normal appearance of the cervix indicates that cervical trauma, cervical neoplasm and inevitable miscarriage are not the cause.
Placenta praevia describes a placenta lying wholly or partly in the lower uterine segment
Epidemiology
5% will have low-lying placenta when scanned at 16-20 weeks gestation
incidence at delivery is only 0.5%, therefore most placentas rise away from cervix
Associated factors
multiparity
multiple pregnancy
embryos are more likely to implant on a lower segment scar from previous caesarean section
Clinical features
shock in proportion to visible loss
no pain
uterus not tender
lie and presentation may be abnormal
fetal heart usually normal
coagulation problems rare
small bleeds before large
Investigations
placenta praevia is often picked up on the routine 20 week abdominal ultrasound
the RCOG recommend the use of transvaginal ultrasound as it improves the accuracy of placental localisation and is considered safe
Classical grading
I - placenta reaches lower segment but not the internal os
II - placenta reaches internal os but doesn’t cover it
III - placenta covers the internal os before dilation but not when dilated
IV - placenta completely covers the internal os
Placental abruption
This patient has had a placental abruption. Important signs and symptoms to think about when suspecting placental abruption are:
continuous abdominal pain
shock disproportionate to the amount of blood loss (20% of placental abruptions are ‘concealed’ - the blood is trapped behind the placenta and does not drain)
the uterus may be in spasm and feel firm or ‘woody’
the fetus may be hard to feel
the fetal heart may be hard to auscultate
Remember that most women giving birth are young and fit - they may not show signs of shock until they have lost a considerable amount of blood as they are able to compensate well.
The pain felt in labour comes in waves with each contraction. You would not expect a woody, tender uterus or low blood pressure.
Placenta praevia is another important cause of antepartum haemorrhage but is typically painless.
Uterine rupture in pregnancy is very rare and is often catastrophic. Risk factors include a scarred uterus - e.g. multiple previous caesarian sections.
Placental insufficiency means the blood flow to the placenta is insufficient for the baby to develop as it should, and can result in intrauterine growth restriction.
Placental abruption describes separation of a normally sited placenta from the uterine wall, resulting in maternal haemorrhage into the intervening space
Epidemiology
occurs in approximately 1/200 pregnancies
Cause - not known but associated factors:
proteinuric hypertension
multiparity
maternal trauma
increasing maternal age
Clinical features
shock out of keeping with visible loss
pain constant
tender, tense uterus
normal lie and presentation
fetal heart: absent/distressed
coagulation problems
beware pre-eclampsia, DIC, anuria
Postpartum haemorrhage
Uterine atony is the most common cause of primary postpartum haemorrhage. It entails failure of the uterus to contract fully following the delivery of the placenta, which hinders the achievement of haemostasis. Uterine atony is associated with overdistension, which may be due to multiple gestation, macrosomia, polyhydramnios or other causes.
In addition to the usual steps taken in an episode of PPH (including an ABC approach if the patient is unstable), the following management should be initiated in sequence:
bimanual uterine compression to manually stimulate contraction
intravenous oxytocin and/or ergometrine
intramuscular carboprost
intramyometrial carboprost
rectal misoprostol
surgical intervention such as balloon tamponade
Postpartum haemorrhage (PPH) is defined as blood loss of > 500mls and may be primary or secondary
Primary PPH
occurs within 24 hours
affects around 5-7% of deliveries
most common cause of PPH is uterine atony (90% of cases). Other causes include genital trauma and clotting factors
Risk factors for primary PPH include*:
previous PPH
prolonged labour
pre-eclampsia
increased maternal age
polyhydramnios
emergency Caesarean section
placenta praevia, placenta accreta
macrosomia
ritodrine (a beta-2 adrenergic receptor agonist used for tocolysis)
Management
ABC including two peripheral cannulae, 14 gauge
IV syntocinon (oxytocin) 10 units or IV ergometrine 500 micrograms
IM carboprost
if medical options failure to control the bleeding then surgical options will need to be urgently considered
the RCOG state that the intrauterine balloon tamponade is an appropriate first-line ‘surgical’ intervention for most women where uterine atony is the only or main cause of haemorrhage
other options include: B-Lynch suture, ligation of the uterine arteries or internal iliac arteries
if severe, uncontrolled haemorrhage then a hysterectomy is sometimes performed as a life-saving procedure
Secondary PPH
occurs between 24 hours - 12 weeks**
due to retained placental tissue or endometritis
*the effect of parity on the risk of PPH is complicated. It was previously though multiparity was a risk factor but more modern studies suggest nulliparity is actually a risk factor
**previously the definition of secondary PPH was 24 hours - 6 weeks. Please see the RCOG guidelines for more details
Post-partum mental health problems
Post-partum mental health problems range from the ‘baby-blues’ to puerperal psychosis.
The Edinburgh Postnatal Depression Scale may be used to screen for depression:
10-item questionnaire, with a maximum score of 30
indicates how the mother has felt over the previous week
score > 13 indicates a ‘depressive illness of varying severity’
sensitivity and specificity > 90%
includes a question about self-harm
‘Baby-blues’
Postnatal depression
Puerperal psychosis
Seen in around 60-70% of women
Typically seen 3-7 days following birth and is more common in primips
Mothers are characteristically anxious, tearful and irritable
Affects around 10% of women
Most cases start within a month and typically peaks at 3 months
Features are similar to depression seen in other circumstances
Affects approximately 0.2% of women
Onset usually within the first 2-3 weeks following birth
Features include severe swings in mood (similar to bipolar disorder) and disordered perception (e.g. auditory hallucinations)
Reassurance and support, the health visitor has a key role
As with the baby blues reassurance and support are important
Cognitive behavioural therapy may be beneficial. Certain SSRIs such as sertraline and paroxetine* may be used if symptoms are severe** - whilst they are secreted in breast milk it is not thought to be harmful to the infant
Admission to hospital is usually required
There is around a 20% risk of recurrence following future pregnancies
*paroxetine is recommended by SIGN because of the low milk/plasma ratio
**fluoxetine is best avoided due to a long half-life
admission to allow psychiatric evaluation.
Whilst there is not a full complement of psychotic features there are a number of pointers towards significant mental health problems:
poor interaction with the baby: this is very unusual, including in women with postnatal depression
‘talking in an incoherent fashion about the future’
stating that the baby ‘has been brought into a very bad world’ is odd and somewhat worrying
For these reasons, the mother should have an urgent psychiatric evaluation.
Post-term pregnancy
The World Health Organization defines a post-term pregnancy as one that has extended to or beyond 42 weeks.
Potential complications/consequences:
Neonatal
Reduced placental perfusion
Oligohydramnios
Maternal
Increased rates of intervention including forceps and caesarean section
Increased rates of labour induction
Pre-eclampsia
Severe pre-eclampsia is associated with hyperreflexia and clonus. A low platelet count may indicate the patient is developing HELLP syndrome
Pre-eclampsia is a condition seen after 20 weeks gestation characterised by pregnancy-induced hypertension in association with proteinuria (> 0.3g / 24 hours). Oedema used to be third element of the classic triad but is now often not included in the definition as it is not specific
Pre-eclampsia is important as it predisposes to the following problems
fetal: prematurity, intrauterine growth retardation
eclampsia
haemorrhage: placental abruption, intra-abdominal, intra-cerebral
cardiac failure
multi-organ failure
NICE divide risk factors into high and moderate risk:
High risk factors
Moderate risk factors
hypertensive disease in a previous pregnancy
chronic kidney disease
autoimmune disease, such as systemic lupus erythematosus or antiphospholipid syndrome
type 1 or type 2 diabetes
chronic hypertension
first pregnancy
age 40 years or older
pregnancy interval of more than 10 years
body mass index (BMI) of 35 kg/m² or more at first visit
family history of pre-eclampsia
multiple pregnancy
Features of severe pre-eclampsia
hypertension: typically > 170/110 mmHg and proteinuria as above
proteinuria: dipstick ++/+++
headache
visual disturbance
papilloedema
RUQ/epigastric pain
hyperreflexia
platelet count < 100 * 106/l, abnormal liver enzymes or HELLP syndrome
Management
consensus guidelines recommend treating blood pressure > 160/110 mmHg although many clinicians have a lower threshold
oral labetalol is now first-line following the 2010 NICE guidelines. Nifedipine and hydralazine may also be used
delivery of the baby is the most important and definitive management step. The timing depends on the individual clinical scenario
Pregnancy anaemia
Pregnant women are screened for anaemia at:
the booking visit (often done at 8-10 weeks), and at
28 weeks
NICE use the following cut-offs to determine whether a woman should receive oral iron therapy:
Gestation
Cut-off
Booking visit
< 11 g/dl
28 weeks
< 10.5 g/dl
In pregnancy there are a number of physiological changes that take place and many of these are normal. Ventilation rates are known to increase in pregnancy due to the increased demand for oxygen and the increased basal metabolic rate. Oxygen consumption can increase by as much as 20%.
For the cardiovascular system. Plasma volume increases which results in an increase heart rate, stroke volume and cardiac output. From a haematological point of view the plasma volume increased by up to 50% and the red blood cell volume increase by about 20-30%. Due to this discrepancy, the haematocrit can decrease due to the dilution effect.
Pregnancy and drugs
The table below summarises some of the risks associated with drug use during pregnancy:
Drug
Risks
Smoking
Increased risk of miscarriage
Increased risk of pre-term labour
Increased risk of stillbirth
IUGR
Increased risk of sudden unexpected death in infancy
Alcohol
Fetal alcohol syndrome (FAS)
learning difficulties
characteristic facies: smooth philtrum, thin vermilion, small palpebral fissures
IUGR & postnatal restricted growth
microcephaly
Binge drinking is a major risk factor for FAS
Cannabis
Similar to smoking risks due to tobacco content
Cocaine
Maternal risks
hypertension in pregnancy including pre-eclampsia
placental abruption
Fetal risk
prematurity
neonatal abstinence syndrome
Heroin
Risk of neonatal abstinence syndrome
Pregnancy diabetes mellitus
Diabetes mellitus may be a pre-existing problem or develop during pregnancy, gestational diabetes. It complicates up to 1 in 20 pregnancies. NICE estimate the following breakdown:
- 5% have gestational diabetes
- 5% have type 1 diabetes
5% have type 2 diabetes
Risk factors for gestational diabetes
BMI of > 30 kg/m²
previous macrosomic baby weighing 4.5 kg or above
previous gestational diabetes
first-degree relative with diabetes
family origin with a high prevalence of diabetes (South Asian, black Caribbean and Middle Eastern)
Screening for gestational diabetes
women who’ve previously had gestational diabetes: oral glucose tolerance test (OGTT) should be performed as soon as possible after booking and at 24-28 weeks if the first test is normal. NICE also recommend that early self-monitoring of blood glucose is an alternative to the OGTTs
women with any of the other risk factors should be offered an OGTT at 24-28 weeks
Diagnostic thresholds for gestational diabetes
these have recently been updated by NICE, gestational diabetes is diagnosed if either:
fasting glucose is >= 5.6 mmol/l
2-hour glucose is >= 7.8 mmol/l
Management of gestational diabetes
newly diagnosed women should be seen in a joint diabetes and antenatal clinic within a week
women should be taught about selfmonitoring of blood glucose
advice about diet (including eating foods with a low glycaemic index) and exercise should be given
if the fasting plasma glucose level is < 7 mmol//l a trial of diet and exercise should be offered
if glucose targets are not met within 1-2 weeks of altering diet/exercise metformin should be started
if glucose targets are still not met insulin should be added to diet/exercise/metformin
if at the time of diagnosis the fasting glucose level is >= 7 mmol/l insulin should be started
if the plasma glucose level is between 6-6.9 mmol/l, and there is evidence of complications such as macrosomia or hydramnios, insulin should be offered
glibenclamide should only be offered for women who cannot tolerate metformin or those who fail to meet the glucose targets with metformin but decline insulin treatment
Management of pre-existing diabetes
weight loss for women with BMI of > 27 kg/m^2
stop oral hypoglycaemic agents, apart from metformin, and commence insulin
folic acid 5 mg/day from pre-conception to 12 weeks gestation
aspirin 75mg/day from 12 weeks until the birth of the baby, to reduce the risk of pre-eclampsia
detailed anomaly scan at 20 weeks including four-chamber view of the heart and outflow tracts
tight glycaemic control reduces complication rates
treat retinopathy as can worsen during pregnancy
Targets for self monitoring of pregnant women (pre-existing and gestational diabetes)
Time
Target
Fasting
5.3 mmol/l
1 hour after meals
7.8 mmol/l, or:
2 hour after meals
6.4 mmol/l
NICE have recently changed their gestational diabetes guidelines. Insulin should be started in the fasting glucose is >= 7 mmol/l. Aspirin should also be considered given the increased risk of pre-eclampsia.
Pregnancy: diabetes - complications
Maternal complications
polyhydramnios - 25%, possibly due to fetal polyuria
preterm labour - 15%, associated with polyhydramnios
Neonatal complications
macrosomia (although diabetes may also cause small for gestational age babies)
hypoglycaemia (secondary to beta cell hyperplasia)
respiratory distress syndrome: surfactant production is delayed
polycythaemia: therefore more neonatal jaundice
malformation rates increase 3-4 fold e.g. sacral agenesis, CNS and CVS malformations (hypertrophic cardiomyopathy)
stillbirth
hypomagnesaemia
hypocalcaemia
shoulder dystocia (may cause Erb’s palsy)
Pregnancy jaundice
Intrahepatic cholestasis of pregnancy
Intrahepatic cholestasis of pregnancy (also known as obstetric cholestasis) occurs in around 1% of pregnancies and is generally seen in the third trimester. It is the most common liver disease of pregnancy.
Features
pruritus, often in the palms and soles
no rash (although skin changes may be seen due to scratching)
raised bilirubin
Management
ursodeoxycholic acid is used for symptomatic relief
weekly liver function tests
women are typically induced at 37 weeks
Complications include an increased rate of stillbirth. It is not generally associated with increased maternal morbidity
Acute fatty liver of pregnancy
Acute fatty liver of pregnancy is rare complication which may occur in the third trimester or the period immediately following delivery.
Features
abdominal pain
nausea & vomiting
headache
jaundice
hypoglycaemia
severe disease may result in pre-eclampsia
Investigations
ALT is typically elevated e.g. 500 u/l
Management
support care
once stabilised delivery is the definitive management
Gilbert’s, Dubin-Johnson syndrome, may be exacerbated during pregnancy
HELLP
Haemolysis, Elevated Liver enzymes, Low Platelets
HELLP syndrome is a severe form of pre-eclampsia whose features include: Haemolysis (H), elevated liver enzymes (EL), and low platelets (LP). A typical patient might present with malaise, nausea, vomiting, and headache. Hypertension with proteinuria is a common finding, as well as epigastric and/or upper abdominal pain.
The patient in this scenario fulfils the criteria for HELLP syndrome.
Pruritus is extremely common in pregnancy, affecting as many as a quarter of women. Causes include exacerbations of eczema, polymorphic eruption of pregnancy, or simply just as the result of skin stretching and changes in circulation. Pruritus in the absence of a rash should raise the possibility of obstetric cholestasis. This potentially serious condition increases the risk of complications such as prematurity, passage of meconium, post partum haemorrhage, and possibly stillbirth. Liver function tests and bile acids are therefore the most important tests to check. Iron deficiency anaemia can also cause pruritus so full blood count would also be relevant.
Source: RCOG Obstetric Cholestasis Guidelines
https://www.rcog.org.uk/globalassets/documents/guidelines/gtg43.pdf
Prematurity risks
Risk of prematurity
increased mortality depends on gestation
respiratory distress syndrome
intraventricular haemorrhage
necrotizing enterocolitis
chronic lung disease, hypothermia, feeding problems, infection, jaundice
retinopathy of newborn, hearing problems
This woman is now in premature labour, although at 3cm dilated it is still in an early stage. Therefore, it may be stopped by administering tocolytic medication. In case the labour continues and delivery is required, steroids are given as a pre-emptively to help the foetal lungs mature. Antibiotics are not required as there is no indication of an infection. Syntocinon injection contains oxytocin which strengthens the contractions of the uterus!
Puerperal pyrexia
Puerperal pyrexia may be defined as a temperature of > 38ºC in the first 14 days following delivery.
Causes:
endometritis: most common cause
urinary tract infection
wound infections (perineal tears + caesarean section)
mastitis
venous thromboembolism
Management
if endometritis is suspected the patient should be referred to hospital for intravenous antibiotics (clindamycin and gentamicin until afebrile for greater than 24 hours)
Streptococcus agalactiae - also known as group B streptococcus - is the commonest cause of severe, early-onset neonatal infection. This condition still remains fairly uncommon however, with an incidence of 0.5/1000 births. The majority of affected infants present with symptoms of sepsis within the first 12 hours after birth. Blood cultures should be taken before antibiotic treatment is commenced, and lumbar puncture should be considered to identify cases of meningitis. Risk factors for neonatal group B streptococcal disease include prolonged rupture of membranes, maternal intrapartum fever and previous pregnancy affected by group B streptococcus. The mortality of early-onset group B streptococcal disease is approximately 10%, so early recognition and treatment is vital.
[RCOG Green-Top Guideline No. 36]
Rhesus negative pregnancy
A basic understanding of the pathophysiology is essential to understand the management of Rhesus negative pregnancies
along with the ABO system the Rhesus system is the most important antigen found on red blood cells. The D antigen is the most important antigen of the rhesus system
around 15% of mothers are rhesus negative (Rh -ve)
if a Rh -ve mother delivers a Rh +ve child a leak of fetal red blood cells may occur
this causes anti-D IgG antibodies to form in mother
in later pregnancies these can cross placenta and cause haemolysis in fetus
this can also occur in the first pregnancy due to leaks
Prevention
test for D antibodies in all Rh -ve mothers at booking
NICE (2008) advise giving anti-D to non-sensitised Rh -ve mothers at 28 and 34 weeks
the evidence base suggests that there is little difference in the efficacy of single-dose (at 28 weeks) and double-dose regimes (at 28 & 34 weeks). For this reason the RCOG in 2011 advised that either regime could be used ‘depending on local factors’
anti-D is prophylaxis - once sensitization has occurred it is irreversible
if event is in 2nd/3rd trimester give large dose of anti-D and perform Kleihauer test - determines proportion of fetal RBCs present
Anti-D immunoglobulin should be given as soon as possible (but always within 72 hours) in the following situations:
delivery of a Rh +ve infant, whether live or stillborn
any termination of pregnancy
miscarriage if gestation is > 12 weeks
ectopic pregnancy (if managed surgically, if managed medically with methotrexate anti-D is not required)
external cephalic version
antepartum haemorrhage
amniocentesis, chorionic villus sampling, fetal blood sampling
abdominal trauma
Tests
all babies born to Rh -ve mother should have cord blood taken at delivery for FBC, blood group & direct Coombs test
Coombs test: direct antiglobulin, will demonstrate antibodies on RBCs of baby
Kleihauer test: add acid to maternal blood, fetal cells are resistant
Affected fetus
oedematous (hydrops fetalis, as liver devoted to RBC production albumin falls)
jaundice, anaemia, hepatosplenomegaly
heart failure
kernicterus
treatment: transfusions, UV phototherapy
In surgical management of an ectopic pregnancy then Anti-D immunoglobulin should be administered.
Anti-D is not required in circumstances where a medical management of the ectopic has been used, nor for treatment of pregnancy of unknown location.
Coombs test:
Direct Coombs: Is a investigation used to look for autoimmune haemolytic anaemia,
Indirect: Used antenatally to detect antibodies in the maternal blood that can cross the placenta and result in haemolytic disease of the newborn.
Rubella and pregnancy
Rubella, also known as German measles, is a viral infection caused by the togavirus. Following the introduction of the MMR vaccine it is now rare. If contracted during pregnancy there is a risk of congenital rubella syndrome. Remember that the incubation period is 14-21 days and individuals are infectious from 7 days before symptoms appear to 4 days after the onset of the rash.
Risk
in first 8-10 weeks risk of damage to fetus is as high as 90%
damage is rare after 16 weeks
Features of congenital rubella syndrome
sensorineural deafness
congenital cataracts
congenital heart disease (e.g. patent ductus arteriosus)
growth retardation
hepatosplenomegaly
purpuric skin lesions
‘salt and pepper’ chorioretinitis
microphthalmia
cerebral palsy
Diagnosis
suspected cases should be discussed immediately with the local Health Protection Unit (HPU) as type/timing of investigations may vary
IgM antibodies are raised in women recently exposed to the virus
it should be noted that it is very difficult to distinguish rubella from parvovirus B19 clinically. It is therefore important to also check parvovirus B19 serology as there is a 30% risk of transplacental infection, with a 5-10% risk of fetal loss
Management
suspected cases of rubella in pregnancy should be discussed with the local Health Protection Unit
since 2016, rubella immunity is no longer routinely checked at the booking visit
if a woman is however tested at any point and no immunity is demonstrated they should be advised to keep away from people who might have rubella
non-immune mothers should be offered the MMR vaccination in the post-natal period
MMR vaccines should not be administered to women known to be pregnant or attempting to become pregnant
This scenario is now rare due to the widespread uptake of the MMR vaccination. It does however still occur, particularly in immigrant communities.
Shoulder dystocia
Shoulder dystocia is a complication of vaginal cephalic delivery. It entails inability to deliver the body of the fetus using gentle traction, the head having already been delivered. Shoulder dystocia is a cause of both maternal and fetal morbidity. It is associated with postpartum haemorrhage and perineal tears with respect to the former, and brachial plexus injury with respect to the latter, amongst other complications. Neonatal death occasionally occurs.
Key risk factors for shoulder dystocia include fetal macrosomia, high maternal body mass index, diabetes mellitus and prolonged labour. It usually occurs due to impaction of the anterior fetal shoulder on the maternal pubic symphysis. Additionally help should be called as soon as shoulder dystocia is identified and McRoberts’ manoeuvre should be performed. This manoeuvre entails flexion and abduction of the maternal hips, bringing the mother’s thighs towards her abdomen. This rotation increases the relative anterior-posterior angle of the pelvis and often facilitates a successful delivery.
An episiotomy will not relieve the bony obstruction but is sometimes used to allow better access for internal manoeuvres. Symphysiotomy and the Zavanelli manoeuvre can cause significant maternal morbidity and are not first-line options. Oxytocin administration is not indicated in shoulder dystocia.
(RCOG Green-top Guideline No. 42)
A shoulder dystocia occurs when after delivery of the head the fetus becomes stuck, usually by the anterior shoulder. It is an obstetric emergency.
Initial management involves McRoberts manoeuvre. An episiotomy is required if this is unsuccessful.
An emergency cesarean section would not routinely be offered in this situation as the newborns head would have already have been delivered. Note, there are four categories of cesarean section. Category 1: Emergency with immediate threat to life. Category 2: Urgent with maternal or fetal compromise. Category 3:Scheduled meaning early delivery is required but there is no threat to life. Category 4: Elective.
Intrauterine Growth
Symphysis-fundal height
The symphysis-fundal height (SFH) is measured from the top of the pubic bone to the top of the uterus in centimetres
It should match the gestational age in weeks to within 2 cm after 20 weeks, e.g. if 24 weeks then the a normal SFH = 22 to 26 cm
An amniotic fluid volume of 440ml indicates oligohydramnios. Tracheo-oesophageal fistula is associated with polyhydramnios.
Oligohydramnios
In oligohydramnios there is reduced amniotic fluid. Definitions vary but include less than 500ml at 32-36 weeks and an amniotic fluid index (AFI) < 5th percentile.
Causes
premature rupture of membranes
fetal renal problems e.g. renal agenesis
intrauterine growth restriction
post-term gestation
pre-eclampsia
Intrauterine growth restriction is a cause of oligohydramnios
Importance: 82
This patient has oligohydramnios as her amniotic fluid is <500ml at 32 weeks. Intrauterine growth restriction is a cause of oligohydramnios.
Multiple gestations is a cause of polyhydramnios.
Oesophageal atresia is a cause of polyhydramnios due to inability to swallow.
Batter syndrome is associated with polyhydramnios.
Maternal diabetes is associated with polyhydramnios.
