Magnesium sulfate for 6 vs 24 hours post delivery in patients who received magnesium sulfate for less than 8 hours before birth: a randomized clinical trial

Background: To compare the benefits of magnesium sulfate for 24 h (h) postpartum versus 6 h postpartum in patients who received magnesium sulfate (Mg) for less than 8 h before birth.

Methods: A randomized, multicenter, open study was conducted between November 2013 and October 2016 in three teaching maternity hospitals in Panama. Pregnant women diagnosed with severe pre-eclampsia or pre-eclampsia with severe features at more than 20 weeks gestation were invited to participate. They were randomized to the following groups in a 1:1 ratio: A- continue Mg for 24 h after birth (control group); and B- receive Mg for 6 h after birth (experimental group). The primary endpoint and variable was seizure (eclampsia) in the first 72 h postpartum.

Results: During the study period, 284 patients agreed to participate in the study; 143 were randomized to receive Mg for 24 h postpartum and 141 to receive Mg for 6 h postpartum. There were no significant differences in the baseline characteristics of the two groups studied. There was no eclampsia in the entire population; therefore, there was no significant difference in the primary variable. Two secondary variables showed a significant difference: time to onset of ambulation, which was 14 h shorter (p = 0.0001) in the group that received 6 h of postpartum Mg, and time to initiation of breastfeeding, which was 11 h earlier (p = 0.0001) in the group that received 6 h of postpartum Mg. There were not significant differences between the groups with respect to total complications or any particular complication. There were no cases of maternal death.

Conclusion: Maintaining Mg for 6 h postpartum is equally effective in preventing eclampsia as receiving Mg for 24 h postpartum in patients with severe pre-eclampsia who receive less than 8 h of Mg treatment before birth. The onset of maternal ambulation and initiation of breastfeeding are faster in patients who only receive Mg for 6 h postpartum.

Trial registration: The study was registered at clinical-trials.gov, number NCT02317146 . Date of registration: December 11, 2014. This study was registered at clinical trials after the beginning of recruitment of patients.