Severe preeclampsia at 34 weeks with an unfavourable cervix
A 32-year-old woman, gravida 2 para 1, attends obstetric triage at 34 weeks and 3 days with a severe frontal headache and blurred vision for 6 hours. Blood pressure is 174/112 mmHg on two readings 15 minutes apart, with 3+ proteinuria on dipstick. Reflexes are brisk with two beats of clonus and there is mild facial puffiness. Platelets 94 × 10^9/L, AST 96 U/L, ALT 88 U/L, creatinine 92 µmol/L, uric acid 428 µmol/L, LDH 402 U/L, haemoglobin 108 g/L. Urine output over the last 3 hours is 80 mL. Cardiotocography shows a baseline of 150 beats/min, normal variability and no decelerations. The cervix is 1 cm dilated, 30% effaced, station −3, Bishop score 3. Estimated fetal weight on the 32-week scan was on the 30th centile. She weighs 88 kg and is 160 cm tall. She has received no magnesium sulphate and no antihypertensive treatment. The labour ward has one empty theatre and a level 2 neonatal unit.
1. Classify her condition and decide between delivery now and expectant management. Show your reasoning.
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Severe preeclampsia with severe features, at 34+3 weeks, with an unfavourable cervix.
The features that make this severe rather than non-severe:
- Blood pressure 174/112 mmHg on repeated readings (systolic ≥160 or diastolic ≥110).
- Symptoms: persistent headache and visual disturbance.
- Thrombocytopenia 94 × 10^9/L, transaminases roughly twice the upper limit of normal, LDH elevated.
- Hyperreflexia with clonus, and oliguria (about 27 mL/h).
- Uric acid 428 µmol/L supports the diagnosis and correlates with severity.
Delivery is indicated, after stabilisation, and expectant management is not appropriate. The purpose of expectant management in preeclampsia is to gain fetal maturity; at 34+3 weeks with neurological symptoms, thrombocytopenia and hepatic involvement, the maternal risk of eclamptic seizure, abruption, HELLP progression and pulmonary oedema outweighs a small gain in gestational age, and there is no fetal compromise on CTG that would justify waiting for steroids to complete.
What stabilisation means: magnesium sulphate loading, blood pressure control to below 160/110 mmHg, a working cannula and group and save, and a clear plan for delivery within 24 hours. A single course of antenatal betamethasone is reasonable while delivery is being organised - evidence at 34–36 weeks shows reduced respiratory morbidity and it does not require delaying delivery - but the decision to deliver must not be postponed to complete it.
2. Write your magnesium sulphate and antihypertensive prescriptions, and list the observations that keep her safe.
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Magnesium sulphate (Zuspan regimen)
- Loading dose 4 g intravenously over 20 minutes (16 mmol), then 1 g/h by infusion for 24 hours after delivery or after the last seizure, whichever is later.
- No dose adjustment needed at creatinine 92 µmol/L, but if renal function declines the infusion should be reduced and levels checked.
- Recurrent seizure: a further 2–4 g over 5 minutes.
Antihypertensives - target 130–150/80–100 mmHg, never below 130/80
- Labetalol 200 mg orally, repeating after 30 minutes if needed; or intravenous labetalol 20 mg, then 40–80 mg at 10-minute intervals to a maximum of 300 mg.
- Hydralazine 5–10 mg intravenously over 20 minutes if labetalol is unavailable or contraindicated.
- Nifedipine 10 mg orally as an alternative.
- Avoid ACE inhibitors, angiotensin receptor blockers and diuretics.
Monitoring on the labour ward
- Respiratory rate (stop and review if below 12/min), oxygen saturation, deep tendon reflexes, hourly urine output (intervene if below 25–30 mL/h) and conscious level.
- Continuous CTG while on magnesium; the fetus may show reduced variability, which is expected and should not by itself trigger caesarean section.
- Fluid restriction: total intake around 80 mL/h including all infusions - these women develop pulmonary oedema easily, especially postpartum.
- Antidote at the bedside: 10 mL of 10% calcium gluconate for suspected toxicity.
- Repeat platelets, liver enzymes and renal function 12-hourly; falling platelets or rising transaminases should prompt reassessment for HELLP syndrome.
3. Decide the mode of delivery, then outline her postpartum and long-term plan.
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Mode of delivery
- The CTG is normal and there is no abruption or fetal growth restriction requiring immediate delivery, so induction of labour is reasonable despite a Bishop score of 3. Ripen the cervix with a transcervical balloon catheter or vaginal misoprostol per local protocol, with continuous monitoring and a low threshold for caesarean section for fetal compromise or failure to progress.
- Caesarean section is indicated if the CTG becomes abnormal, if she deteriorates, if platelets fall far enough to make regional anaesthesia unsafe, or if induction fails. Theatre is available now, so do not let the unit's capacity drive an unnecessary caesarean.
- Check a full blood count immediately before any regional anaesthesia; with platelets around 94 × 10^9/L and a stable trend, neuraxial anaesthesia is usually acceptable, but a rapidly falling count changes that.
- Ensure magnesium is running before induction or before transfer to theatre.
Postpartum
- Continue magnesium for 24 hours after delivery; the risk of seizure is highest in the first 24–48 hours.
- Blood pressure often peaks on days 3–5, so do not discharge before a documented stable reading; arrange a review at 1 week and again at 6 weeks.
- Thromboprophylaxis based on risk score; counsel about contraception, avoiding combined oestrogen methods if hypertensive.
Long-term
- Recurrence risk in a future pregnancy is around 15–20%, with earlier onset likely; start low-dose aspirin (75–150 mg) from 12 weeks in the next pregnancy and arrange early booking.
- Explain the lifelong cardiovascular risk: annual blood pressure and weight checks, and screening for diabetes and dyslipidaemia.
- Debrief her about what happened; women who have had severe preeclampsia frequently carry significant psychological distress and unanswered questions.