Clinical overview
Medical disorders complicating pregnancy are a leading cause of maternal death in South Africa. The Saving Mothers reports of the NCCEMD consistently identify non-pregnancy-related infections (dominated by HIV and its sequelae — pneumonia, tuberculosis), obstetric haemorrhage, and hypertension as the top contributors, with medical and surgical disorders forming a substantial avoidable fraction. Many deaths are judged avoidable: late presentation, failure to recognise the sick pregnant woman, delayed referral up the levels of care, and substandard monitoring recur as themes. The registrar's task is to anticipate decompensation, because pregnancy lowers physiological reserve and masks early warning signs — a tachycardia or breathlessness that would alarm in a non-pregnant patient is too easily dismissed as "normal pregnancy".
This chapter is deliberately broad: a survey of the common medical complications named in the objective, each treated to the depth a registrar needs to triage, stabilise, and refer correctly within the South African four-tier system (clinic/CHC → district → regional → tertiary). Several of these conditions are full emergencies — DKA, thyroid storm, eclampsia/HELLP, severe pneumonia, massive PE — and the drills for those are flagged explicitly. The unifying principle is the National Integrated Maternal and Perinatal Care Guideline (NDoH, 2024): risk-stratify at booking, manage the mother first (a dead mother delivers no live baby), and escalate early.
Core knowledge
Physiological pregnancy adaptations that change interpretation
- Plasma volume rises ~40–50% more than red-cell mass, producing a dilutional fall in haemoglobin (physiological anaemia of pregnancy).
- Cardiac output rises ~30–50%, heart rate climbs, and a mild resting tachycardia is normal.
- Respiratory alkalosis (progesterone-driven hyperventilation) is the baseline; a "normal" PaCO₂ in an asthmatic or septic woman may signal impending failure.
- Hypercoagulability (rising fibrinogen, factors VIII/IX/X, falling protein S, venous stasis) raises VTE risk several-fold.
- Renal plasma flow and GFR rise, lowering normal creatinine and urea; relative glycosuria and ureteric dilatation predispose to UTI/pyelonephritis.
- Insulin resistance rises across gestation (human placental lactogen, cortisol, progesterone), unmasking gestational and worsening pre-existing diabetes.
Figure J24.1 — Pregnancy adaptations that change interpretation of common symptoms and tests.
Condition-specific essentials
Anaemia is haemoglobin below the trimester-specific threshold; iron deficiency dominates, but in SA also consider HIV, chronic infection, and haemoglobinopathy. The classical WHO/standard cut for anaemia in pregnancy is Hb <11 g/dL, with severe anaemia conventionally taken as Hb <7 g/dL — verify the exact threshold and trimester adjustment against the NDoH guideline.
UTI spans asymptomatic bacteriuria, cystitis, and pyelonephritis. Asymptomatic bacteriuria matters in pregnancy because it progresses to pyelonephritis far more often than outside pregnancy and is associated with preterm birth and low birthweight — hence screening and treatment.
VTE (DVT and pulmonary embolism) is a leading direct cause of maternal death in well-resourced settings. Risk is present from the first trimester and is highest postpartum. RCOG GTG 37a/37b frame risk assessment and acute management.
Diabetes is either pre-existing (type 1/2) or gestational (GDM). Pre-existing diabetes carries congenital-anomaly and miscarriage risk tied to periconceptional glycaemia; GDM is a disorder of glucose tolerance first recognised in pregnancy (NICE NG3).
Asthma often runs a "rule of thirds" course (a third improve, worsen, or stay the same). Poorly controlled asthma — not the inhalers — harms the fetus.
Pneumonia and TB: pregnancy is relatively immunosuppressed; in SA, TB and HIV co-infection drive maternal morbidity and feature heavily in Saving Mothers.
Epilepsy: seizure control and teratogenicity must be balanced (RCOG GTG 68). Sodium valproate is highly teratogenic and broadly contraindicated in women of childbearing potential.
Hypertensive disorders / HELLP: HELLP (Haemolysis, Elevated Liver enzymes, Low Platelets) is a severe variant of pre-eclampsia — covered fully in Pre eclampsia and HELLP and Hypertension in pregnancy; managed per NICE NG133 and the NDoH guideline.
Obesity (RCOG GTG 72) amplifies almost every other risk: GDM, pre-eclampsia, VTE, anaesthetic difficulty, shoulder dystocia, wound sepsis, stillbirth.
Depression and perinatal mental illness are common, under-detected, and a recognised contributor to maternal death (including suicide) — see GBV and mental health in pregnancy.
DKA can occur at lower glucose levels in pregnancy ("euglycaemic DKA") and threatens the fetus profoundly; it is an emergency.
Thyroid disease (RCOG GTG 76): hypothyroidism needs prompt replacement; thyroid storm is a rare, lethal decompensation of hyperthyroidism.
Proteinuria is a cardinal sign of pre-eclampsia and renal disease; quantify it, do not eyeball it.