Obstetrics Flashcards
Risk factors for a PPH
5 P…RIME …
Prolonged labour Pre-eclampsia Previous PPH Polyhydraminos Placenta Praevia Ritodrine (b2 agonist used for tocolysis .. suppressing premature labour) Increased Age Macrosomic baby Emergency caesarian
Define PPH
500 ml of blood lost from the genital tract within 24h after delivering the baby
What is a secondary postpartum haemorrhage (SPH)
Haemorrhage 24h - 12 weeks after delivering the baby due to retained placenta or endometritis
How to Mx a PPH
1) 2 large bore cannulae (14 gauge)
2) IV oxytocin (10IU) or IV ergometrine (500ug) (contracts uterus)
3) IM carboprost
4) Intrauterine balloon tamponade (if due to uterine atony)
4) B-lynch suture
5) Ligate uterine or iliac arteries
6) Hysterectomy as last/life saving resort
High risk factors for pre-eclampsia
HTN in previous pregnancy CKD Autoimmune disease (SLE, antiphospholipid) Type 1/2 DM Chronic HTN
Moderate risk factors for pre-eclampsia
First pregnancy or pregnancy interval of >10 years >40 y/o BMI >35 at first visit Multiple pregnancy Family history of pre-eclampsia
Potential maternal consequences of pre-eclampsia
Eclampsia
Haemorrhage (placental abruption, intra-abdominal, intra-cerebral)
Cardiac failure
Multi-organ failure
Potential fetal consequences of pre-eclampsia
Prematurity IUGR (intra-uterine growth retardation)
What is pre-eclampsia?
HTN and proteinuria >20 weeks gestation +/- oedema
Clinical features of pre-eclampsia
HTN typically >170/110 Proteinuria (++ or +++) Headache Visual disturbance Papilloedema RUQ pain / epigastric pain Hyper-reflexia Low platelet count / Elevated liver enzymes / HELLP syndrome
What is HELLP syndrome?
Haemolysis (H), Elevated Liver Enzymes (EL) & Low Platelets (LP) (thrombocytopenia)
Life-threatening complication of pregnancy! Thought of as a variant of pre-eclampsia…
Presents in a similar way to pre-eclampsia
Mx of pre-eclampsia
Labetalol
Hydralazine
Nifedipine
Mx of HELLP syndrome?
DELIVER THE BABY
What is vasa praevia
Fetal blood vessels cross/run near to the internal orifice of the uterus. Can be compromised following membrane rupture!
How does vasa praevia present?
Membranes ruptured
Painless vaginal bleeding
Bradycardia of the fetus
Risk factors for neural tube defects
Diabetes Mellitus Previous child with neural tube defect Women on antiepileptic medications Obesity HIV + taking co-trimoxazole Sickle cell
Mx of women who have higher risk of neural tube defects
5mg Folic Acid
Causes of a baseline bradycardia on CTG
Increased fetal vagal tone
Maternal beta blocker use
Causes of a baseline tachycardia on CTG
Maternal pyrexia
Chorioamionitis
Hypoxia
Prematurity
Causes of a loss of baseline variability on CTG
Prematurity
Hypoxia
Causes of early decelerations on CTG
Head compression, not a concerning feature
What is an early deceleration on CTG
Deceleration which commences with the onset of contraction and returns to normal on completion of the contraction
Causes of a late deceleration on CTG
Fetal distress - asphyxia, placental insufficiency
What is a late deceleration on CTG?
Deceleration of heart rate which lags before the onset of a contraction and does not return to normal until after 30 seconds following the end of the contraction
Causes of variable decelerations on CTG
Cord compression
What is a normal fetal heart rate on CTG
100-160 bpm
What is a galactocele
Cystic lesion in the breast due to occlusion of a lactiferous duct (milk builds up). Painless lump. Firm and non tender. No surrounding skin changes.
Test findings for an expected trisomy 21 pregnancy
Low AFP Low oestriol High b-HCG Low PAPP-A (pregnancy associated plasma protein A) Thickened nuchal translucency
Mx of parvovirus b19/slapped cheek syndrome in pregnant women
Can affect an unborn baby in the first 20 weeks of pregnancy.
If a woman is exposed early in pregnancy (before 20 weeks) she should seek prompt advice from whoever is giving her antenatal care as maternal IgM and IgG will need to be checked.
Fetal consequences of parvovirus b19 (erythema infectiosum/slapped cheek) in pregnancy
Haemolysis
Hydrops fetalis
Intrauterine death (IUD)
When is ergometrine contra-indicated in PPH? and why?
Hypertension / pre-eclampsia / eclampsia
Why ? It contracts smooth muscle and will make htn worse
What conditions can raise AFP on screening?
Gastric wall defects (omphalocele, gastroschisis)
Open neural tube defects
Multiple pregnancy
What conditions can cause a low AFP on screening?
Down’s syndrome
Trisomy 18 (Edward’s syndrome)
Maternal diabetes mellitus
List some causes of oligohydramnios
PROM (premature rupture of membranes) Renal agenesis (fetus) IUGR Pre-eclampsia Post term gestation
Define oligohydramnios
Definitions vary but include less than 500ml at 32-36 weeks and an amniotic fluid index (AFI) < 5th percentile.
What is fetal fibronectin?
Protein released from the gestational sac. Thought to be a sign of early labour.
What would warrent a continuous CTG throughout labour?
If any of the following arise in labour:
- suspected chorioamnionitis or sepsis, or a temperature of 38°C or above
- severe hypertension 160/110 mmHg or above
- oxytocin use
- the presence of significant meconium
- fresh vaginal bleeding that develops in labour
What drug should be given to all women with PPROM?
Erythromycin 10 days
Corticosteroids for baby’s lung maturity if she goes into preterm labour
Investigations if you suspect intra-uterine fetal death?
REAL TIME USS (look for fetal heart beat)
Investigate cause in the mother:
- FBC, CRP, LFT, TFT, Clotting and thrombophilia screen, Cultures, antiphospholipid antibodies, anti-d antibodies
- Urine dip and MC&S
- STI swabs
- Hba1c
- Kelihauer test
- Viral screen TORCH (Toxoplasmosis, CMV, Rubella, Herpes)
Investigations / Tests on fetus after a stillbirth?
Genetic karyotyping
Fetal and placental swabs (infection)
Offer postmortem examination of the baby
Causes of stillbirth
No cause found in ~30%
Fetal:
- Genetic abnormalities
- Infection
- Twin-twin transfusion syndrome
Maternal:
- Rhesus disease
- Obstetric cholelithiasis
- Chronic disease in pregnancy
- HTN
- Thrombophilia
Placental:
- Abruption
- Pre-eclampsia (insufficiency due to inadequate trophoblast invasion doesn’t generate low resistance system)
- Cord prolapse
- APH
What support is offered to parents after a stillbirth?
Bereavement counselling, support groups
Asked if they would like a lock of hair, palm print and to hold the baby. Naming the baby can help with grieving.
Offer hospital funeral for the baby (paid for by hospital)
Financial support: can still claim maternity leave/pay and maternity allowance
Define a stillbirth
Babies that are born dead after 24 weeks gestation
How is a baby delivered in a stillbirth/IUD?
80% spontaneous labour in 2 weeks and 90% go into spontaneous labour within 3 weeks
Induction of labour (mifepristone + misoprostol +/- oxytocin) and thromboprophylaxis (high risk of coagulopathy). Be sensitive, find a room away from the sound of babies.
Causes of oligohydramnios
Reduced amniotic fluid surrounding fetus (for gestational age) … due to reduced fetal urine production or increased amniotic fluid loss
- Placental insufficiency (pre-eclampsia, smoking, diabetes)
- Renal agenesis / renal tract abnormality
- Rupture of membranes
List some complications of oligohydramnios
IUGR
Pulmonary hypoplasia
Foetal compression syndrome
How is amniotic fluid measured?
AFI (amniotic fluid index)
Risk factors for developing gestational diabetes?
Prev history of GDM Asian, afro-carribean or middle eastern ethnicity BMI >30 Prev history of macrosomic baby PMH- PCOS FMH (first degree relative of GDM)
When and how to test for GDM?
OGTT at 28 weeks if at risk!
If a woman has had previous GDM she may be offered an OGTT at booking.
Diagnosed if fasting glucose >5.6mmol/l or 2 hour glucose >7.8mmol/l (2hrs after being given a drink with 75g glucose)
Pathogenesis of GDM
In pregnancy metabolism / glucose requirements increase to support fetus. This causes an initial increase in insulin sensitivity and fat deposition in the first trimester.
Then in the second trimester the placenta produces anti-insulin hormones (cortisol, placental lactogen) which increase insulin resistance and serum glucose levels rise (for the fetus). This increase in resistance stimulates the pancreas to produce more insulin.
GDM occurs when the pancreas is unable to produce enough insulin to overcome the insulin resistance and maternal hyperglycaemia develops… and consequently fetal hyperglycaemia and hyperinsulinaemia.
What are the fetal complications associated with GDM?
Polyhydramnios (due to fetal polyuria)
Macrosomia (due to fetal hyperinsulinaemia and hyperglycaemia) and increased risk of shoulder dystocia in labour
IUGR (placental vascular dysfunction)
IUD Congenital abnormalities (CVS and neuro due to insulin resistance in organogenesis)
RDS - (delayed surfactant production)
Hypoglycaemia (due to hyperinsulinaemia which develops in response to maternal hyperglycaemia)
Mx of GDM in pregnancy
Lifestyle and diet changes
Metformin = only oral hypoglycaemic approved
Insulin to maintain glycaemic control if metformin not successful. Insulin should be stopped after delivery as maternal insulin requirements fall immediately after delivery.
Should aim for a fasting glucose of 4-6mmol/l and a post-prandial glucose of 7.8mmol/l
Induction of labour around 38 weeks (and continuous ctg monitoring throughout labour)
LSCS offered if estimated fetal weight >4.5kg
How many mothers with GDM will develop T2DM post partum?
50% - do a 6 week postpartum fasting glucose and then annual fasting glucose tests with GP
What are the preconception folic acid recommendations for women with pre-existing diabetes mellitus?
5mg (due to increased risk of neural tube defects)
Preconception advice for a woman with existing diabetes mellitus?
5mg folic acid up until 12 weeks gestation
Check retinopathy/nephropathy at booking as this may be worsened throughout pregnancy
Alter medications - stop oral hypoglycaemics. Only metformin and insulin are approved for pregnancy.
What is different about scans done in GDM compared to low risk pregnancy
More regular growth scans due to the risk of fetal macrosomia or IUGR
Detailed CVS scan done at the 18-20 week anomaly scan due to risk of CVS defects
Why might seizures become more frequent during pregnancy?
Reduced sleep - reduced seizure threshold
Vomiting (altered drug levels)
Increased plasma volume (altered drug levels)
What prenatal advice should be given to a woman with epilepsy?
Higher dose of folic acid due to increased risk of neural tube defects (5mg till 12 weeks gestation)
Aim to be seizure free for 2 months prior to conception
Monotherapy with either lamotrigene or carbamazepine
How is labour managed in a woman with epilepsy?
Regular CTG monitoring
Avoid use of Pethidine as this reduces seizure threshold (use diamorphine instead)
Give birth in a consultant led obstetric unit as the risk of seizures is highest in labour
Postnatal advice for a woman who is epileptic?
Risk of seizures is higher in the postpartum period (take the appropriate precautions, bath not shower, change baby on the floor etc)
Breastfeeding is safe on AEDs
Contraception advice (OCPs are metabolised by CYP450 so effectiveness may be reduced by AEDs which induce CYP450… carbamazepine, phenytoin)
Fetal complications of maternal epilepsy / seizures
Miscarriage / threatened miscarriage
Congenital malformations due to AEDs (neural tube defects, microcephaly, cardiac defects)
Low IQ and developmental delay
Low birthweight / IUGR
Death
What % of women with epilepsy have an abnormal pregnancy / fetal abnormality ?
<10%
What physiological changes occur in the thyroid gland and thyroid hormone levels during pregnancy?
Hypertrophies and becomes more vascular (this reverses after pregnancy)
T3 and T4 rise due to an increase in TBG and as b-HCG has TSH effects (cross reactivity). Rarely symptomatic and usually resolves by 20 weeks when bHCG has dropped.
If you suspected Graves disease in a pregnant woman what signs would you look for?
Thyroid acropachy
Exopthalmos
Proptosis
Pre-tibial myxodema
What is the risk of Graves disease in pregnancy?
IgG antibodies (against TSH receptor) can cross the placenta and cause hyperthroidism in the fetus
They are removed from the fetal circulation by 8 weeks postpartum and signs of fetal hyperthyroidism wear off
Complications of hyperthyroidism in pregnancy
Maternal: May develop thyrotoxic storm at delivery/anaesthesia Tachycardia/arrhythmia Miscarriage /stillbirth Pre-eclampsia
Fetal: Prematurity Fetal thyrotoxicosis Fetal hyperthyroidism- may see tachycardia, Low birth weight/IUGR
What medication is safest to use to control hyperthyroidism (Grave’s) in pregnancy?
Propylthiouracil (not teratogenic and less likely to cross the placenta). Associated with maternal hepatotoxicity.
Carbimazole isn’t often used due to risk of fetal bone disorder and it can cross the placenta and cause fetal hypothyroidism. Thought to be safe in later trimesters after fetal bone development.
Radioactive iodine is contraindicated
Can breastfeed on propylthiouracil and carbimazole
What increases the risk of transient gestational hyperthyroidism
Molar pregnancy - due to high bhCG
Transient gestational hyperthyroidism is related to bHCG levels and as a result rarely responds to anti-thyroid medications.
Usually resolves by 20 weeks when bhCG has fallen
Can use b-blockers for symptomatic relief however women are normally asymptomatic
What is post partum thyroiditis
Abnormal TSH level in first 12 months postpartum in the absence of antibodies or toxic thyroid nodule
More likely to occur in the presence of TPO antibodies
Mild hyperthyroidism -> hypothyroidism -> euthyroid state
Antithyroid medications rarely helpful, give symptomatic relief with beta blockers
Usually self resolves within 6 months
Complications of hypothyroidism in pregnancy
Miscarriage / still birth
PPH
Premature birth
Reduced infant IQ
If severe: can cause fetal cretinism (deafness, growth restriction, severe neurodevelopmental dysfunction)
Signs of neonatal hypothyroidism
Excessive sleepiness
Reduced muscle tone
Infrequent bowel movements / constipation
Jaundice
Reduced body temperature
Umbilical hernia or macroglossia o/e if severe
Management of hypothyroidism in pregnancy
Levothyroxine replacement immediately
(fetal thyroid gland doesnt develop until 12 weeks so it is dependent on maternal thyroxine until then, can cause abnormal brain development if low)
Can ACE inhibitors be used in pregnancy?
No - contraindicated as they are associated with fetal abnormalities such as renal agenesis.
Alternatives for HTN management include labetalol, nifedipine and methyldopa
Risk factors for hyperemesis gravidarum
Molar pregnancy
Multiple pregnancy
Obesity
Hyperthyroidism
- BhCG level related directly to severity
** Smoking reduces risk
How to score the severity of hyperemesis gravidarum?
PUQE score
Triad needed to diagnose hyperemesis gravidarum
5% pre-pregnancy weight loss
Dehydration
Electrolyte imbalance (hyponatraemic, hypokalaemic)
**presence of ketones also warrants admission
Management of hyperemesis gravidarum?
1st line = antihistamine antiemetics (promethazine and cyclizine)
2nd line = ondansetron, metoclopramide
When is hyperemesis gravidarum likely to occur?
8-12 weeks
May persist up till 20 weeks
RARE to persist past 20 weeks
Complications of hyperemesis gravidarum
Wernicke’s encephalopathy (B1 deficiency)
Central pontine demyelination (correct low Na too fast)
Mallory-Weiss tear
Acute tubular necrosis
Fetus: SGA
Management of late decelerations?
Urgent fetal blood sampling
Late decelerations = pathological, need to assess for fetal acidosis (pH <7.2 in labour)
CTG findings which are indicators for an emergency c-section?
Terminal bradycardia - baseline rate <100 for >10 minutes
Terminal deceleration - heart rate drops and does not recover for >3 minutes
Varicella zoster virus (chickenpox) exposure in pregnancy
1) Test for immunity (varicellar antibodies)
2) If not immune can give single dose varicellar immunoglobulin (up to 10 days post exposure)
3) If she presents with the chicken pox rash within 24h of onset = oral aciclovir
Complications of varicella zoster infection in pregnancy
Maternal:
- Increased risk of pneumonitis
Fetal:
- Fetal varicellar syndrome (limb hypoplasia, eye defects, learning difficulties, skin scarring)
- Shingles in infancy if mother exposed in 2nd/3rd trimester
- Fatality of neonatal varicella if mother infected 5 days pre-delivery or 2 days post-delivery
What is Mendelson’s syndrome?
Inhalation of gastric contents during general anaesthesia causing:
- bronchospasm
- tachycardia
- cyanosis
- pulmonary oedema
(similar presentation to amniotic fluid embolus)
Mx:
- Tilt on side to aspirate pharynx
- Aminophylline infusion and hydrocortisone
- Bronchoscopy to clear bronchi under GA with antibiotic cover
- May need ventilating on ICU
Drugs which should be avoided in breast feeding?
- Amiodarone
- Sulfonylureas
- Methotrexate
- Cytotoxic drugs
- Carbimazole
- Aspirin
- Lithium
- Benzodiazepines
- Abx (cipro, tetracyclines, sulphonamides, chloramphenicol)
