Severe Preeclampsia at 34 Weeks
28-year-old G2P1 at 34 weeks and 2 days by dating ultrasound presents with a 2-day history of frontal headache and new visual blurring. Her blood pressure is 168/112 mmHg, confirmed on two readings 15 minutes apart. She has 2+ proteinuria on dipstick and a spot urine protein/creatinine ratio of 1.2. She has no epigastric pain, no seizures, and no vaginal bleeding. Reflexes are brisk with 2 beats of clonus; lungs are clear. Platelets 92,000/µL, AST 96 U/L, ALT 110 U/L, creatinine 1.1 mg/dL, hemoglobin 11.2 g/dL. Fetal heart rate tracing is category I with a baseline of 142 beats/min, no decelerations, and no contractions on toco. The cervix is closed, long, and posterior. She has no prior history of hypertension and no known drug allergy. The unit has magnesium sulfate, labetalol, hydralazine, nifedipine, and a level III neonatal unit.
1. What is the diagnosis, and what immediate drug treatment should be started before delivery?
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This is severe preeclampsia with severe features at 34+2 weeks. Severe features are present because of systolic BP ≥160 mmHg, headache and visual symptoms, platelets below 100,000/µL, and elevated transaminases. The normal fetal tracing is reassuring but does not change the maternal diagnosis. Start magnesium sulfate for seizure prophylaxis: 4-6 g IV loading dose over 20 minutes, then 1-2 g/hour infusion. Monitor deep tendon reflexes, respiratory rate, urine output, and oxygen saturation; keep calcium gluconate at the bedside. Treat severe hypertension with labetalol 10-20 mg IV, hydralazine 5-10 mg IV, or oral nifedipine 10 mg, aiming for 130-150/80-100 mmHg rather than a precipitous drop. Give betamethasone 12 mg IM, repeated in 24 hours, because she is below 34-36 weeks and steroids reduce neonatal respiratory morbidity. Insert a Foley catheter, monitor fetal heart rate, and repeat platelets, liver enzymes, and creatinine. Avoid ACE inhibitors, ARBs, and diuretics unless there is pulmonary edema. Fluids should be restricted because of the risk of pulmonary edema.
2. When and how would you deliver, and what factors determine the route?
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At 34 weeks or beyond with severe features, delivery is recommended. If maternal and fetal status remain stable, give the steroid course and deliver within 24-48 hours; do not pursue prolonged expectant management. Delivery should be immediate if there is uncontrollable hypertension, HELLP syndrome with deteriorating labs, abruption, eclampsia, pulmonary edema, or a non-reassuring fetal tracing. The route depends on cervical favourability, fetal status, and maternal condition. This cervix is closed, long, and posterior, so induction may be prolonged; caesarean delivery is reasonable if urgent delivery is needed or if induction fails. Vaginal delivery is not contraindicated and can be attempted if the cervix becomes favourable and there is no fetal compromise, with magnesium continuing and BP controlled. Neuraxial anesthesia is generally safe if platelets are above about 70,000-80,000/µL and there is no coagulopathy, but the platelet trend must be checked because it can fall quickly. The decision should be made jointly by obstetrics, anesthesia, and neonatology.
3. On magnesium sulfate she becomes drowsy, has a respiratory rate of 10/min, and absent knee jerks. How do you manage this, and what else would you monitor?
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This is magnesium toxicity. Stop the magnesium infusion immediately, call for help, give oxygen, and support ventilation if needed. Give calcium gluconate 1 g IV over 10 minutes as the antidote; this is 10 mL of 10% calcium gluconate. Check magnesium level and renal function, because magnesium is renally excreted and toxicity is more likely with renal impairment. Do not restart magnesium until reflexes return, respiratory rate is above 12-16/min, and urine output is adequate. Monitor hourly urine output, deep tendon reflexes, respiratory rate, oxygen saturation, and fetal heart rate. If magnesium is restarted, use a lower infusion rate and recheck levels. Continue postpartum seizure prophylaxis for at least 24 hours or longer if eclampsia occurred. Also monitor blood pressure, platelets, liver enzymes, and postpartum bleeding, because the risk of HELLP and postpartum hemorrhage persists after delivery. Document the toxicity event and counsel the patient.