Why does haemoglobin fall in a normal pregnancy? ANSWER: because PLASMA VOLUME rises proportionally more than red cell mass. 1. Both plasma volume and red cell mass increase in pregnancy. 2. Plasma volume increases MORE. 3. So the concentration of haemoglobin falls — a DILUTION effect. CONSEQUENCE FOR PRACTICE: the non-pregnant threshold for anaemia does not apply. Using it labels healthy pregnant women as anaemic, and may misjudge women who are genuinely depleted. Use the pregnancy-specific threshold in your national guideline. This chapter deliberately quotes no cut-off, since values differ between trimesters and between sources.

Why is antenatal anaemia dangerous even when the woman is asymptomatic? ANSWER: because it removes the RESERVE she needs at delivery. 1. Every woman loses blood when she delivers. 2. A woman with normal haemoglobin tolerates that comfortably. 3. An anaemic woman may not tolerate the SAME volume at all. 4. A postpartum haemorrhage that would have been survivable becomes fatal — particularly where blood is not immediately available. AND WHY TIMING MATTERS: oral iron takes WEEKS to raise haemoglobin meaningfully. Anaemia found at booking can be corrected; the same anaemia found at term cannot, and she enters labour without reserve. DO NOT ASSUME IRON DEFICIENCY ALONE: consider hookworm, malaria, thalassaemia, and B12 or folate deficiency by setting.

A baby born to a mother with gestational diabetes becomes jittery two hours after birth. What is the most likely cause, and why? ANSWER: NEONATAL HYPOGLYCAEMIA. MECHANISM — one fact explains it: Glucose crosses the placenta. INSULIN DOES NOT. 1. Maternal hyperglycaemia delivers a high glucose load to the fetus. 2. The FETUS responds by producing its own insulin. 3. At birth the cord is cut and the maternal glucose supply stops abruptly. 4. But the baby's high insulin production CONTINUES for a time. 5. Glucose falls. THE SAME MECHANISM explains MACROSOMIA — fetal insulin is a growth factor — and therefore the risk of SHOULDER DYSTOCIA at delivery. ACTION: check the baby's blood glucose after birth.

A woman with known rheumatic mitral stenosis has coped well through pregnancy. When is she at greatest risk? A. First trimester B. Second trimester C. Labour and the immediate postpartum period D. Six weeks after delivery ANSWER: C — labour and the immediate postpartum period. Why: delivery of the PLACENTA returns a large volume of blood to the maternal circulation ABRUPTLY. A heart that coped with the gradual increase of pregnancy can be overwhelmed by that sudden shift. This is counter-intuitive: the pregnancy has gone well, so the risk feels as though it is passing at exactly the moment it peaks. CONTEXT: rheumatic heart disease remains a common underlying cause in many settings, and a woman may not know she has valve disease. Ask about childhood rheumatic fever.

Which symptom in a breathless pregnant woman suggests pathology rather than normal pregnancy? A. Breathlessness on climbing stairs B. Ankle swelling in late pregnancy C. Breathlessness lying flat, or waking her at night D. A soft systolic murmur ANSWER: C — orthopnoea and paroxysmal nocturnal breathlessness. Why: A, B and D are all features of NORMAL pregnancy. Increased cardiac output produces a flow murmur; venous compression produces ankle swelling; exertional breathlessness is expected. NORMAL PREGNANCY DOES NOT CAUSE ORTHOPNOEA. Breathlessness lying flat or waking her at night suggests cardiac failure and needs assessment. Also significant: chest pain, syncope, and a murmur that is loud or DIASTOLIC.

A woman with epilepsy on long-term medication tells you she is 8 weeks pregnant. Should her antiepileptic be stopped? ANSWER: No — not reflexively. This requires specialist review, not withdrawal. THE TENSION: Some antiepileptics carry teratogenic risk. BUT uncontrolled seizures endanger both mother and fetus — a seizure causes hypoxia, and status epilepticus is life-threatening. AND NOTE THE TIMING: at 8 weeks, much of organogenesis has already occurred. Stopping now does not undo an exposure that has happened, but it does create a new risk of seizures. THE REAL LESSON: this decision should have been made BEFORE conception. Ask every woman of childbearing age with a chronic illness about her plans, and review the regimen while there is still time for the review to matter.

Why is pre-conception care more valuable than early antenatal care for a woman with diabetes? ANSWER: because ORGANOGENESIS is largely complete before many women realise they are pregnant, and certainly before the first antenatal visit. WHAT ACTS IN THAT EARLY WINDOW: - glucose control at the time of conception - a drug review swapping a teratogenic agent for a safer one - folate supplementation - optimisation of thyroid, cardiac or renal disease By the booking appointment, that window has usually closed. PRACTICAL INSTRUCTION: ask every woman of childbearing age with a chronic illness whether she is planning a pregnancy — and if she might be, review her treatment now rather than later.