Medical Disorders in Pregnancy and Obstetric Emergencies
Core concepts
Medical disorders complicate pregnancy and change thresholds for treatment. Hypertensive disorders: preeclampsia is new hypertension after 20 weeks with proteinuria or end-organ dysfunction. Severe features include systolic ≥160 mmHg, diastolic ≥110 mmHg, thrombocytopenia, renal insufficiency, impaired liver function, pulmonary edema, or visual/cerebral symptoms. Magnesium sulfate is the drug of choice for seizure prophylaxis and treatment; monitor reflexes, respiratory rate, and urine output. Diabetes: preconception control reduces malformations; gestational diabetes is screened at 24–28 weeks. Cardiac disease: pregnancy increases plasma volume and cardiac output; the highest risk is around delivery and the postpartum period. Venous thromboembolism risk rises markedly; use LMWH when indicated. Emergencies include hemorrhage, sepsis, amniotic fluid embolism, uterine inversion, and shoulder dystocia.
Traps
Do not wait for proteinuria to diagnose severe preeclampsia if severe features are present. Do not give ACE inhibitors or warfarin in pregnancy. Magnesium toxicity is suggested by loss of deep tendon reflexes, respiratory depression, and oliguria; calcium gluconate is the antidote. In sepsis, antibiotics and source control should not be delayed by fetal concerns.
Worked example
A woman at 34 weeks has a blood pressure of 168/112 mmHg, platelets 90,000/µL, and headache. She has preeclampsia with severe features. Management: intravenous magnesium sulfate, antihypertensives such as labetalol or hydralazine to keep blood pressure below 160/110, corticosteroids, and delivery after stabilization.
Rule of thumb: in preeclampsia, the cure is delivery; the timing depends on maternal and fetal status, not on a single blood pressure reading.