Is there benefit to continue magnesium sulphate postpartum in women receiving magnesium sulphate before delivery? A randomised controlled study.

Abstract

To determine if the use of magnesium sulphate postdelivery reduces the risk of eclampsia in women with severe pre-eclampsia exposed to at least 8 hours of magnesium sulphate before delivery. Randomised multicentre controlled trial. Latin America. Women with severe pre-eclampsia that had received a 4-g loading dose followed by 1 g per hour for 8 hours as maintenance dose before delivery. In all, 1113 women were randomised; 555 women were randomised to continue the infusion of magnesium sulphate for 24 hours postpartum and 558 were randomised to stopping the magnesium sulphate infusion immediately after delivery. Primary outcome was the incidence of eclampsia in the first 24 hours postdelivery. Secondary outcomes included maternal death, maternal complications, time to start ambulation and time to start lactation. The maternal characteristics at randomisation between the groups were not different. There were no differences in the rate of eclampsia; 1/555 (0.18%) versus 2/558 (0.35%) [relative risk (RR 0.7, 95% CI 0.1-3.3; P = 0.50] or maternal complications between the groups (RR 1.0, 95% CI 0.8-1.2; P = 0.76). Time to start ambulation was significantly shorter in the no magnesium sulphate group (18.1 ± 10.6 versus 11.8 ± 10.8 hours; P = 0.0001) and time to start lactation was equally shorter in the no magnesium sulphate group (24.1 ± 17.1 versus 17.1 ± 16.8 hours; P = 0.0001). Women with severe pre-eclampsia treated with a minimum of 8 hours of magnesium sulphate before delivery do not benefit from continuing the magnesium sulphate for 24 hours postpartum. No benefit of continuing magnesium sulphate postpartum in severe pre-eclampsia exposed to this drug for a minimum of 8 hours before delivery.