Duration of postpartum magnesium sulfate for seizure prophylaxis in women with preeclampsia: a systematic review and meta-analysis

Objective: Pregnant women diagnosed with preeclampsia are at increased risk of eclampsia. Magnesium sulfate is the standard of care for maternal seizure prophylaxis. Traditional regimens of magnesium sulfate have continued infusions for 24 h postpartum. More recent evidence suggests shortened courses of postpartum magnesium sulfate. The purpose of this systematic review is to evaluate whether the duration of postpartum magnesium sulfate for seizure prophylaxis in women with preeclampsia affects the incidence of seizures postpartum. Data source: MEDLINE, Cochrane Library, and clinicaltrials.gov were reviewed from inception until 1 May 2020. Methods of study selection: Two hundred and fifty-three studies were reviewed by three individual authors. Inclusion criteria were as follows: published, randomized controlled trials (RCTs) that included pregnant women diagnosed with preeclampsia who received a maintenance infusion of magnesium sulfate in the postpartum period. Studies were excluded if either arm did not provide maintenance dosing of magnesium sulfate in the postpartum period. We also excluded ongoing, unpublished, and non-randomized trials. Results: Nine RCTs (n = 1369) were included in the systematic review. Data were abstracted and reviewed by three authors, then entered into Review Manager data software. The primary outcome of eclampsia was reported in all nine studies. An eclamptic event occurred in 2/696 women who received <24 h of postpartum magnesium compared to 0/673 events in women who received ≥24 h of postpartum magnesium (RD 0.00, 95% CI −0.01, 0.01; p=.71). Women who received <24 h of postpartum magnesium sulfate had a significantly faster time to ambulation postpartum (MD −10.57, 95% CI −17.43, −3.71; p=.003) and shorter durations of indwelling urinary catheter placement (MD −18.97, 95% CI −34.64, −3.29; p=.02). Conclusions: As eclampsia is a rare occurrence, this review was not powered to show a difference in the rate of eclampsia. However, the two cases of eclampsia that were reported occurred in the group of women who received <24 h of postpartum magnesium sulfate. Therefore, the results of this systematic review support continued use of 24 h of postpartum magnesium sulfate for seizure prophylaxis.