obstetrics Flashcards
Name the urine and blood tests at booking
MSU - dipstick for blood and protein
Hb, blood group and antibody screen
BBV - syphilis, rubella, HIV
Consider sickle cell test, Hb electrophoresis for haemoglobinopathy, 25-hydroxyvitamin D if relevant.
At what gestation do you screen for chromosomal and structural abnormalities?
Booking (11-13+6)
What investigations should be performed at every antenatal visit?
Urine dipstick for protein, BP, fundal height.
When are Hb and Rh antibodies tested and what is administered?
Test all Rh- mothers for antibodies at booking
give anti-D if needed at 28 and 34 weeks
From what gestation should a Kleihauer test be performed to determine foetal RBC leak?
20+0
Anti-D should be given within 72h of which situations
Delivery of a Rh+ infant Any TOP or miscarriage after 12wks Surgical mx of miscarriage/ectopic at any gestation ECV APH or abdo trauma Amniocentesis/CVS/Foetal blood sampling
What measurements are used to date pregnancy?
Crown-rump length at 6-12wks
Biparietal diameter 14-34wks (peaks in accuracy at 20wks)
Causes of increased nuchal translucency
Down’s syndrome
congenital heart defect
abdominal wall defect
What is the underlying aneuploidy in Edward’s syndrome, describe the clinical presentation
trisomy 18
rarely survive 1yr, micrognathia, low set ears, rocker bottom feet, overlapping fingers
What is the underlying aneuploidy in Patau’s syndrome and describe the clinical presentation
trisomy 13
die soon after birth, microcephalic, cleft lip/palate, exomphalos, holoprosencephaly, polydactyly.
What does the combined test consist of and when should it be performed?
11-13+6 weeks
NT + serum b-hcg + Pregnancy Associated Plasma Protein A.
You are in antenatal clinic with a 37 year old woman, G6P4 who is 15 weeks gestation and missed her booking appointment. She has stated she would like screening for Down’s syndrome and other trisomy. What test is used?
15-20wks
triple/quadruple test - AFP + unconjugated estradiol + hCG (± inhibin-A)
In antenatal clinic you are counselling a lady who is currently 12+2 and has just been informed that the combined test indicates the foetus to have T21. You have mentioned invasive testing to confirm the diagnosis.
Describe what is involved in each test and what gestational periods can they be performed in?
Chorionic Villus Sampling - 11-14/40 - transabdominal (rarely transcervical) needle to retrieve cell sample from placenta. Not recommended in dichorionic pregnancy
Amniocentesis - 15-18/40 - US guided needle aspirates amniotic fluid to analyse foetal cells shed by skin/gut.
Both yield results in 3 working days (few weeks in rarer disease needing enzyme/gene probe analysis). Risks - increased rates miscarriage (less so in amniocentesis), BBV transmission.
Define hyperemesis gravidarum, at what gestation would you expect it to occur?
Persistent vomiting in pregnancy causing dehydration, electrolyte imbalance and weightloss (>5% from pre-pregnancy weight). Most common between 8 and 12 weeks, can persist up to 20wks.
Risk factors for hyperemesis gravidarum
multiple pregnancy, trophoblastic disease, previous Hyperemesis Gravidarum, primiparity, obesity, hyperthyroidism
How might someone with hyperemesis gravidarum present?
Persistent vomiting, unable to keep food/fluid down, weightloss, dehydration, tachycardia, postural hypotension, hypovolaemia, hyponatraemia, hypokalaemia, ketoacidosis, polyneuritis (vit B deficiency)
When should you consider admission for someone with hyperemesis gravidarum?
If they are on oral anti-emetics but still have persistent vomiting and are:
- Unable to keep fluid/anti-emetics down
- still displaying ketonuria/weightloss/severe electrolyte imbalance
- confirmed or suspected co-morbidity e.g. UTI
Ix in suspected hyperemesis gravidarum
Urine - MSU for infection and ketones
Blood - FBC (increased haematocrit), U+Es (hypo-natraemia/kalaemia)
How would you manage hyperemesis gravidarum?
Admission if needed to correct electrolyte imbalance/dehydration
IV fluids - 0.9% saline, Na+ and K+ guided by daily U+;Es
Anti-emetics - antihistamine (promethazine)/cyclizine, consider corticosteroids if intractable.
Additional - 5mg folic acid, thiamine/pabrinex for Wernicke encephalopathy, if in hospital thromboprophylaxis (e.g. enoxaparin) and TEDs
What inheritance pattern does sickle cell disease show?
Autosomal recessive
What is sickle cell disease?
Haemoglobinopathy which predisposes to sickling of RBCs in low O2 conditions leading to vaso-occlusion in small vessels and a tendency to haemolytic
Give 5 risks associated with sickle cell disease in pregnancy
Increased risk of perinatal mortality, premature labour, IUGR, painful crises inc acute chest syndrome, increased risk of haemolytic disease of newborn
How does acute chest syndrome present?
Cough, tachypnoea, chest pain and CXR shows new infiltrates.
A 27 year old woman with known sickle cell disease comes to the GP to discuss getting pregnant, what are some investigations/interventions which should be performed prenatally?
Assess current disease:
- ECHO less than 1yr old for pulm htn
- BP and urinalysis
- U+Es and LFTs
- retinal screening
Prophylactic abx and update vaccines (HBV, HiB, MenC, pneumococcal, influenza) due to increased risk infection
Start 5mg folic acid and stop ACEi/A2A drugs and hydroxycarbimide >3/12 pre-conception
Should someone with SCD take aspirin?
Yes from 12 weeks gestation to reduce risk pre-eclampsia 75mg OD
What anti-depressants are the safest in pregnancy?
SSRIs - in particular sertraline
What foetal risks are associated with sertraline use?
Small risk of congenital heart disease with use in T1, persistent pulmonary hypertension with use in T3 and tiny risk of neonatal withdrawal (breastfeeding helps)
Which of the following anti-depressant is safest in breastfeeding mothers: A) Sertraline B) Paroxetine C) Fluoxetine D) Citalopram
Sertraline
Paroxetine should not be used due to risk of cardiac malformation in T1, fluoxetine and citalopram both present in high conc in breast milk
What congenital malformations are associated with sodium valproate use?
Neural tube defects, craniofacial abnormalities, neurodevelopmental problems
Women should not breastfeed while taking lamotrigine true or false?
False, breastfeeding is generally considered safe with the exception of barbiturates.
Lithium use during pregnancy risks what 3 conditions in the newborn?
heart defect including ebsteins anomaly
neonatal thyroid abnormality
floppy baby syndrome
What dose of folic acid should women on anti-epileptics be on and when should they start taking it?
5mg 3 months pre-conceptually
A 27 year old G1P0 lady with a history of bipolar disorder comes to antenatal clinic. Having previously tried other mood stabilisers, lithium seems to be the only agent that works and for that reason she feels it is safer for her and her child to stay on lithium despite the risk of congenital malformations. Counsel her on what this means for her antenatal care and labour
detailed foetal anomaly scan should be offered with foetal echo ~wk6 and 18
lithium levels will be monitored 4-weekly until 36 weeks and form then on measured weekly
Lithium will be stopped during labour and restarted based on 12h post dose level
NO breastfeeding!
When are pregnant women screened for anaemia? what levels define anaemia during pregnancy?
booking <110g/l
week 28 <105g/l
physiological decrease in Hb steepest at 20wks
Risk factors for anaemia during pregnancy
pre-existing anaemia, frequent pregnancies, multiple pregnancy, poor diet
investigations for anaemia during pregnancy
FBC, iron studies (IDA = decreased serum iron, TIBC, serum ferritin), folate (increased MCV, decreased serum and ref cell folate)
What is the most common cause of anaemia during pregnancy?
iron deficiency, then folate deficiency
How would you manage iron deficiency anaemia in pregnancy?
PO ferrous sulphate 200mg BD - can take every other day if GI s/e
not tolerated = ?parenteral iron but can cause anaphylaxis so only administer if CPR facility hand. Late severe anaemia <90 may require blood transfusion
Risk factors for HIV vertical transmission
Breastfeeding, vaginal delivery, ROM >4h, viral load >400 copies/ml, seroconversion during pregnancy, advanced disease, preterm labour, HCV
How do you minimise risk of vertical transmission of HIV mom to baby?
Elective C-section (can consider vaginal if on HAART and viral load <400 /not on and <50)
Bottle-feeding not breast feeding
Maternal anti-retrovirals
A G1P0 lady is found to be HIV+ from her booking bloods. What is your immediate management?
Discuss starting anti-retrovirals to start before 24wks and continue until at least delivery
Screen for and treat any genital infections whether symptomatic or not
Ensure up to date non-live vaccines - flu, pneumococcal, HBV.
What HbA1c should women aim for before getting pregnant?
=<6.1% (43)
at what HbA1c would you advise a woman to avoid getting pregnant?
> = 10%
A 26 year old lady with diabetes comes to you for a medication review as she plans to start trying to get pregnant in the next few months. What medications would you stop/start?
Stop statins, ace inhibitors/a2as, all oral hypoglycaemic except metformin
Start high dose 5mg folic acid
What should you screen for prenatally in a diabetic woman planning to get pregnant?
Nephropathy and retinopathy
Give 4 maternal risks of diabetes
Hypoglycaemia unawareness - especially during 1st trimester
pre-eclampsia
infection
increased rates of c-section
Give 6 foetal risks of diabetes
Miscarriage Malformation Macrosomia/IUGR Polyhydramnios Prematurity Stillbirth
How often should a woman with diabetes during pregnancy attend growth scans?
Every 4 weeks from 28 weeks
When should a pregnant diabetic woman measure BMs
On waking (fasting), pre-meal and 1hr post-prandial for every meal, and bedtime.
What are the target capillary BMs for pregnant diabetic women - fasting, and post-prandial?
fasting 5.3mmol/l
post-prandial either 7.8 at 1h, 6.4 at 2.
What level should BM be intra-partum?
4-7mmol/l, if it is not maintained at this consider IVI - insulin and dextrose.
When should you aim to deliver a baby of a diabetic mother?
37-38+6 if type 1/2
By 40+6 if GDM
What diabetes medications can be used while breastfeeding?
Metformin, insulin, glibenclamide
Risk factors for gestational diabetes
Hx of GDM in prior pregnancy, prev macrosomic baby weighing >4.5kg, BMI>30, certain ethnicities (Middle Eastern, Caribbean, south asian), first degree relative with diabetes
How is gestational diabetes diagnosed?
Oral glucose tolerance test 7.8mmol/l or fasting glucose 5.6mmol/l
When does screening for GDM occur?
At 24-28 weeks for any woman with risk factor for GDM, an additional test at booking if hx GDM
How do you manage GDM?
fasting glucose >7 = immediately start on insulin as well as diet and exercise changes.
Fasting glucose 5.6-7 - trial 1-2 weeks of lifestyle modifications, if this does not work then add metformin, then add insulin.
Normal pregnancy mimics hyper or hypo thyroidism? how and why?
Hyper - goitre, anxiety, tachycardia, warm moist skin
- Increased TBG and T4 output to maintain free T4 levels
- high levels hCG mimic TSH
Risks associated with hyperthyroidism during pregnancy
Harder to conceive, prematurity and miscarriage
What changes are made to the medication of someone with hypothyroidism when they become pregnant? How are they monitored?
Aim for TSH <2.5mmol/l.
Usually require higher dose of levothyroxine
Monitor every 4-6weeks during pregnancy, usually return to pre-pregnancy dose levothyroxine postpartum
A 27 year old woman comes in c/o tonsillitis. Hx = odynophagia, pyrexia (38). PMH hyperthyroidism. Dhx - NKDA, carbimazole.
How would you manage this patient?
FBC for agranulocytosis due to carbimazole
Which of the thyroid medications is considered safest to use during breastfeeding - levothyroxine or carbimazole
levothyroxine, in hyperthyroidism pylthiouracil is preferred during T1 (less transplacental transfer) and breastfeeding.
A 40 year old lady G4P2 30/40 comes to the GP c/o unbearable itchiness which is preventing her sleeping and asks for antihistamines. She says it does affect her palms, soles and abdomen. O/E she is slightly jaundiced.
What is the likely diagnosis and how would you investigate?
Intrahepatic cholestasis of pregnancy - pruritis affecting abdomen, palms and soles, jaundice in 3rd trimester.
Ix - FBC, LFTs (mildly raised), bile acids (mildly raised), virology (Hep A/B/C, EBV, CMV), autoimmune screen (anti-smooth muscle and anti-mitochondrial for chronic hepatitis, primary biliary cirrhosis), liver USS
How would you manage obstetric cholestasis?
Offer elective IOL at 37+0 with continuous elective foetal monitoring intrapartum.
Sx’atic relief - ursodeoxycholic acid. Otherwise symptoms resolve within days of delivery.
How would you expect acute fatty liver of pregnancy to present? What is the general outline of management?
3rd trimester/immediately following delivery
abdo pain, jaundice, N+V, headache ± thrombocytopenia, pancreatitis. Associated pre-eclampsia in 30-60%. Elevated ALTs
Mx - supportive rx liver/renal failure and hypoglycaemia, correct clotting, monitor BP, once stable expedite delivery
What is HELLP syndrome?
Haemolysis, elevated liver enzymes, low platelets. Serious condition develops late in pregnancy, can follow pre-eclampsia.
Sx - N+V, malaise, RUQ/epigastric pain, dark urine, htn
Ix - FBC (low platelets), LFTs (increased), bilirubin (increased), LDH (increased)
Mx - deliver the baby
A booking urine dip has found asymptomatic bacteriuria in a 12+6/40 woman. How should it be treated?
7 day course nitrofurantoin to prevent pyelonephritis which can cause IUGR, prematurity or foetal death.
At what point gestation is nitrofurantoin and trimethoprim used and why?
T1 use nitrofurantoin as trimethoprim is an anti-folate
T3 use trimethoprim as nitrofurantoin risks HDN
Why is pyelonephritis more common in pregnant women/
dilatation of the upper renal tract
how might pyelonephritis present in a pregnant woman? How is it managed?
Can present as urinary frequency and malaise or more dramatically with N&V, loin pain, pyrexia/rigors. Take blood and urine culture, start IV cefuroxime awaiting sensitivities, IV abx for at least 24h and oral for 2-3 weeks.
A 19/40 G1P0 presents with a second confirmed UTI during this pregnancy, what is your next step?
Renal USS and consider prophylactic abx e.g. low dose oral amoxicillin.
Causes of seizure in pregnancy
Eclampsia Epilepsy Intracranial mass Infection Stroke Hypoglycaemia/Hyponatraemia
Management of epilepsy in pregnancy
Can consider stopping AEDs if no seizure for 2yrs, otherwise aim for monotherapy on lowest dose of safest agent (e.g. LTG, basically not valproate/carbamazepine) and start 5mg folic acid 3/12 pre-conception.
Vitamin K in last 4wks of pregnancy if on - phenytoin, ethosuximide, carbamazepine (hepatic enzyme inducers reducing vit K dependent clotting factors increasing risk HDN) and vit K to newborn
Avoid early discharge (risk fit highest in first 24h), encourage breastfeeding, gradually reduce AED dose to pre-natal levels.
How does antiphospholipid syndrome present and how do you diagnose?
Hx venous/arterial thrombosis, recurrent miscarriage (3+ unexplained <10/40, 1 >10/40), thrombocytopenia, prolonged APTT, lupus anticoagulant/anti-cardiolipin/anti-B2 glycoprotein antibodies on 2 tests taken 8 weeks apart.
Mx antiphospholipid syndrome in pregnancy
Specialist management
Regular growth scans + doppler flow studies from 20wks
Aspirin 75mg OD and LMWH e.g. enoxaparin from when foetal heart identified.
Postpartum LMWH/warfarin (can breastfeed on either)
Who should take aspirin 75mg OD from 12/40 and why
Those at high risk pre-eclampsia:
hypertensive disease during previous pregnancy
CKD
autoimmune disorder e.g. antiphospholipid/SLE
DM1/2
What is the physiological pattern of blood pressure during pregnancy?
Drops during trimester 1, continuing to decrease due to drop in vascular resistance til 20-24 weeks then stroke volume increases = BP rises back to pre-pregnancy levels by term.
How is hypertension in pregnancy defined?
Systolic >140 or diastolic >90 OR an increase of sys>30/dia>15 on booking value.
How is hypertension in pregnancy categorised?
Pre-existing or ‘chronic’ htn - measured as >140/90 before 20wks, no proteinuria/oedema
Pregnancy induced - >140/90 after 20wks, no proteinuria/oedema, usually resolved around ~1m postpartum but increased risk future htn/pre-eclampsia
Pre-eclampsia - pregnancy induced htn + proteinuria (±oedema)
Mx of hypertension in pregnancy
Lifestyle - cut down salt <6g/day (ideally <3), caffeine, smoking cessation, balanced diet, exercise. Weekly BP (aim for <135/85), urine dipstick for protein, FBC, U+Es, LFTs Growth scan and umbilical a doppler every 4 weeks (from 28/presentation) Medication - labetalol (2nd amlodipine 3rd methyldopa) + 75mg aspirin OD from 12 weeks.
A 29 year old women with htn comes to the clinic to discuss getting pregnant, what should you advise her in regard to her medication?
Stop ACEi/ARBs/thiazide diuretics due to risk of congenital malformation and switch to labetalol
Start aspirin at 12wks 75mg OD
Pre-eclampsia predisposes to the following problems…
foetal - IUGR, prematurity Eclampsia Haemorrhage - placental abruption, intra-ado, intra-cerebral cardiac failure multi-organ failure
High risk factors for pre-eclampsia
Hypertensive disorder in previous pregnancy
Chronic htn
CKD
autoimmune disease e.g. SLE, anti-phospholipid synd
DM1/DM2
Moderate risk factors for pre-eclampsia
Primiparity Age 40+ BMI 35+ at booking family hx pre-eclampsia multiple pregnancy
Describe the features of severe pre-eclampsia
Severe htn - typically >160/110 + proteinuria >0.5g/d
Hyperreflexia
RUQ/epigastric pain
Headache, visual disturbance and papilloedema
HELLP syndrome
How is pre-eclampsia treated?
Control BP with labetalol
Give magnesium sulphate to prevent seizures (and by definition eclampsia)
Deliver the baby
At what blood pressure would you admit a pregnant woman to hospital?
160/110
Describe intrapartum/postpartum care for a woman with hypertension
As long as Bp remains <160/110 can let pregnancy go beyond 37wks
AMTS - syntocinon alone, not ergometrine as can cause stroke in htn due to worsening htn.
Check BP on day 1, 2, then once day 3-5, then at 2wks
Stop methyldopa postpartum (risk PND), switch to nifedipine/labetalol/amlodipine if antihypertensive still needed. Aim to keep <150/100, consider reducing/stopping if <130/80
When should VTE risk be assessed
Booking, during each antenatal admission, during labour and postnatally
At what point from conception to post-partum is risk VTE highest?
Postpartum
Risk factors for VTE in pregnancy - pre-existing, obstetric and transient
Pre-existing - thrombophilia, medical co-morbidities (e.g. cancer), age >35, BMI >30, para>3, smoking, varicose veins, paraplegia
Obstetric - multiple pregnancy, pre-eclampsia, prolonged labour, C-section, preterm birth, PPH, stillbirth
Transient - any surgical procedure in pregnancy/puerperium, dehydration (e.g. HG), admission/immobility, ovarian hyperstimulation synd, long distance travel, systemic infection
Who is offered thromboprophylaxis and what thromboprophylaxis would they get?
Any woman with 4 risk factors T1/2 (<28wks), 3 risk factors T3 (>28wks), 2 in postpartum period. LMWH for remainder of pregnancy and 6wks postpartum. Also consider 10d LMWH in any woman who has a c-section.
