Antenatal Care and Maternal-Fetal Medicine
Core concepts
Antenatal care is a risk-stratification exercise. Know the schedule of routine visits, the components of each (blood pressure, fundal height, urine protein, fetal movement, presentation after 36 weeks), and the screening timeline: combined first-trimester screening for aneuploidy, mid-trimester anatomy scan, gestational diabetes screening, and group B streptococcus swab at 36–37 weeks.
Maternal-fetal medicine questions reward a structured approach to the complicated pregnancy: hypertension (chronic vs gestational vs pre-eclampsia), diabetes (pre-gestational vs gestational, and the effect of pregnancy on insulin resistance), red-cell alloimmunisation, fetal growth restriction versus small-for-gestational-age constitution, multiple pregnancy chorionicity, and preterm birth prevention. Understand that chorionicity, not zygosity, drives multiple-pregnancy risk and determines the timing of delivery.
Traps
- Confusing low-dose aspirin (started before 16 weeks for pre-eclampsia prophylaxis) with therapeutic anticoagulation.
- Assuming a normal fundal height excludes growth restriction in a macrosomic or oligohydramnios setting.
- Forgetting that the anatomy scan cannot exclude all anomalies and that soft markers are not diagnostic.
- Applying adult blood-pressure thresholds to pregnancy without noting that pre-eclampsia is defined by new hypertension after 20 weeks plus organ dysfunction.
Worked rule of thumb
For suspected pre-eclampsia, ask three questions in order: (1) Is blood pressure ≥140/90 after 20 weeks? (2) Is there proteinuria or maternal organ dysfunction (thrombocytopenia, renal impairment, liver involvement, pulmonary oedema, neurological symptoms)? (3) Is there fetal compromise? Severe features or fetal compromise mandate delivery, and the gestational age determines steroid administration and magnesium sulphate for seizure prophylaxis - not expectant management beyond the point of maternal risk.
Exam technique
State gestational age, then the diagnosis, then the immediate and definitive management. Examiners award the reasoning, not just the label.