Antepartum Eclampsia

Antepartum eclampsia is a generalised seizure in a woman with preeclampsia before labour, usually between 28 weeks and term. It is caused by cerebral vasospasm and loss of autoregulation. It matters because the fetus is at risk from maternal hypoxia and abruption, and the mother needs stabilisation before delivery.

• A large share of eclampsia occurs before labour.
• Risk factors: severe preeclampsia, first pregnancy, adolescent or age above 35 years, twin pregnancy, no antenatal care.
• Fetal bradycardia after a seizure usually recovers with maternal oxygen.

A woman at 28 weeks or later, not in labour, has a tonic clonic seizure often preceded by headache, visual disturbance or epigastric pain, and has hypertension and proteinuria. After the fit she is drowsy and confused.

• Unconscious for minutes to hours.
• Fetal heart rate may fall for 3 to 5 minutes after the seizure.
• Differential diagnosis: epilepsy, cerebral malaria, meningitis, cerebral venous thrombosis, intracranial haemorrhage, hypoglycaemia, hypertensive encephalopathy.
• Complications: aspiration, hypoxia, stroke, pulmonary oedema, abruption, HELLP syndrome, acute kidney injury, stillbirth, preterm birth, maternal death.

The diagnosis is clinical, with tests to find other causes and organ damage.

• Blood pressure, urine protein, temperature, glucose; malaria test.
• Full blood count and film, creatinine, electrolytes, liver enzymes, lactate dehydrogenase, coagulation screen, group and cross-match.
• CT or MRI of the brain if focal signs, persistent coma or atypical features.
• Ultrasound for fetal presentation, placenta and liquor; cardiotocography once stable.

The principle is airway protection, magnesium sulphate, blood pressure control and delivery within 12 hours of stabilisation.

• Supportive: left lateral position; protect the airway; oxygen 10 to 15 L/minute; two cannulae; urinary catheter with hourly output; total fluids 80 mL per hour; monitor pulse, blood pressure and oxygen saturation every 15 minutes at first.
• Pharmacological: magnesium sulphate 4 g IV over 20 minutes then 1 g per hour for 24 hours after delivery, or where infusion is not possible give 4 g IV plus 10 g IM (5 g in each buttock) then 5 g IM 4-hourly; for a repeat seizure give 2 g IV over 5 minutes; stop for absent reflexes, respiratory rate below 12 per minute or urine below 30 mL per hour, and give calcium gluconate 1 g IV over 10 minutes for toxicity; diazepam 10 mg IV over 2 minutes only if magnesium is unavailable; labetalol 20 mg IV over 2 minutes then 40 mg, 80 mg and 80 mg at 10 minute intervals (maximum 220 mg) or nifedipine immediate release 10 mg oral repeated once after 30 minutes or hydralazine 5 mg IV then 5 to 10 mg every 20 to 30 minutes (maximum 20 mg); betamethasone 12 mg IM twice, 24 hours apart, below 34 weeks; oxytocin 10 IU IM after birth and no ergometrine.
• Procedures: delivery within 12 hours of the seizure after stabilisation; induction with misoprostol 25 micrograms vaginal 6-hourly (maximum 4 doses) or Foley catheter with a 30 mL balloon, then oxytocin 2 mU/minute doubling every 30 minutes to 32 mU/minute; caesarean section if the cervix is unfavourable, there is fetal compromise or labour will not progress; intubation for coma.
• Special groups: kidney disease reduces magnesium to 0.5 g per hour with level monitoring; asthma uses nifedipine instead of labetalol.
• Red flags: repeated seizures, coma, blood pressure 160/110 mmHg or more, abruption, saturation below 94 percent, oliguria, fetal bradycardia lasting beyond 10 minutes.
• Follow-up: high dependency care for 24 to 48 hours after birth; blood pressure at 6 hours, daily for 5 days, then at 2 and 6 weeks; review at 6 weeks; aspirin 150 mg oral at night from 12 weeks in the next pregnancy.