Serum level of magnesium attained in magnesium sulfate therapy for severe preeclampsia

Serum magnesium levels were determined in severe preeclampsia patients who were treated with magnesium sulfate infusion. Forty-four patients with diagnosis of severe preeclampsia between 30-41 weeks gestation, given a conventional 5 g magnesium sulfate intravenous bolus infusion and 1 g/hr continuous infusion and continued 24 hours postpartum, were prospectively studied. The mean pre-treatment magnesium level was 2.3 +/- 0.3 mg/dl which was similar to those reports. The levels measured at 1/2, 1, 2, 4, 12 and 24 hours after initiation of magnesium infusion were 4.8 +/- 0.4, 4.7 +/- 0.4, 4.5 +/- 0.3, 4.7 +/- 0.3, 5.4 +/- 0.3 and 5.9 +/- 0.3 mg/dl respectively. After delivery the levels were measured immediately, 12, and 24 hours and found to be 4.7 +/- 0.4, 4.9 +/- 0.4, and 5.2 +/- 0.3 mg/dl respectively. The serum magnesium levels were also varied with maternal weight, the dose regimen used in our study is appropriate for Asian pregnant women whose body weight usually less than 70 kg.