All cases of preeclampsia must be closely followed until delivery, which should occur by 40 weeks gestation.

Eclampsia, seizure in the setting of preeclampsia, is an indication for emergent delivery. Magnesium sulfate should be used as first-line seizure prophylaxis and treatment. Any patient with severe preeclampsia should be started on magnesium, because it has been proven to prevent progression to eclampsia.²

Dosing for seizure prophylaxis is 4-6 g by intravenous bolus given over 20 minutes, followed by 1-2 g per hour maintenance dosing. Magnesium toxicity is a risk; therefore, magnesium levels, respiratory rate, reflexes, and urinary output must be monitored. Hypotension is a known side effect of magnesium.

In the case of hypermagnesemia (levels 6-8 mEq/L), calcium gluconate 10% solution 10-20 mL can be given to correct effects. Phenytoin also has been studied in eclamptic seizures and shown to be successful, but lack of familiarity and difficulty with dosing regimens in pregnancy, along with required cardiac monitoring in IV dosing, have limited its appeal.

Lorazepam may be used as well, but it has been shown to be less reliable in controlling seizures when compared to magnesium and is associated with fetal CNS depression, which may create problems in case of emergency delivery.³

Antihypertensives should be started in patients with severe hypertension in order to prevent maternal end-organ damage and stroke.

Blood pressure control does not, however, alter the progression of preeclampsia. One retrospective study found systolic blood pressure was 159 to 198 immediately prestroke in 24 of 24 patients.⁴ The suggestion is to initiate antihypertensive therapy in preeclamptic women when the systolic blood pressure is 150 mm Hg and the diastolic blood pressure is 100 mm Hg, or if symptoms may be attributable to elevated blood pressure. Treating mild hypertension may lead to fetal growth impairment; therefore, mild hypertension is better monitored than treated.

Hydralazine is often used for blood pressure control in the admitted patient, although unpredictable hypotension is a known side effect. Dosing begins with 5 mg intravenously, followed by a second dose if the desired effect is not achieved within 20 minutes.

Labetalol (alpha- and beta-adrenergic blocking agent) has fewer side effects (such as reflex tachycardia) and should be considered as first-line therapy.⁵ Dosing of intravenous labetalol should start at 20 mg, followed by increasing doses at 10-minute intervals up to a maximum total dose of 300 mg.