Effect of Magnesium on Glomerular Filtration Rate and Recovery of Hypertension in Women with Severe Preeclampsia

Magnesium sulfate is used for preventing seizures in patients with severe preeclampsia. Previous studies have demonstrated that magnesium plays a significant role in the endothelial function and might have clinically beneficial vasodilating properties.

This study is aimed at evaluating the effect of magnesium sulfate on the glomerular filtration rate (GFR) during the first 24 h after delivery and during the duration of recovery from hypertension in preeclampsia.

Severe preeclamptic patients who had normal serum creatinine levels (0.4-0.8 mg/dL) were included in the study. Twenty-three women with severe preeclampsia were divided into groups of 9, 8, and 6, and given 1.0, 1.5, and 2.0 g/h of magnesium sulfate, respectively. Magnesium sulfate infusion was used as seizure prophylaxis for 24 h after delivery. The cystatin C-based GFR was monitored for 24 h, and the blood pressure was recorded for 12 weeks postpartum.

Despite the minimal improvement of GFR 24-h after treatment initiation, survival analysis demonstrated a statistically significant relationship (log rank, p = 0.04) between magnesium dosage and recovery period from hypertension. The group receiving 2.0 g/h of magnesium experienced the shortest recovery period from hypertension (6.5 ± 1.8 days). Meanwhile, the other groups required 66.0 ± 26.9 and 48.3 ± 15.6 days to recover after 1.0 and 1.5 g/h of magnesium infusion, respectively.

Magnesium sulfate has no impact on GFR improvement during the first 24 h after delivery. However, magnesium maintenance infusion at 2.0 g/h is capable of preventing seizure by optimizing the therapeutic magnesium level (4.8-8.4 mg/dL) and shortening the hypertensive episode in preeclampsia.