Magnesium supplementation and preeclampsia in low-income pregnant women – a randomized double-blind clinical trial

Randomized, double-blind, placebo-controlled trial among low-income, low-risk pregnant women in Recife, Brazil; aged 18–45; singleton pregnancy; gestational age at enrollment 12–20 weeks; low-risk antenatal care; 318 randomized (159 per group) with intention-to-treat analysis.

Magnesium citrate 300 mg daily, oral capsule, started at enrollment (gestational age 12–20 weeks) and continued until delivery.

Magnesium citrate did not reduce preeclampsia incidence. Preeclampsia occurred in 26/143 (18.1%) with magnesium and 29/147 (19.7%) with placebo (OR 0.90; 95% CI 0.48–1.69; p=0.747); no cases of eclampsia. Conclusion: Not effective for preventing preeclampsia in low-income, low-risk pregnant women; appears safe and feasible but does not improve outcome; further research needed.

Power to detect only large effects; post-intervention serum magnesium not measured; single-center, low-income, low-risk population; 28 participants lost to follow-up; limited generalizability.