Calcium supplementation in mild preeclampsia remote from term: a randomized double-blind clinical trial

OBJECTIVE: To determine whether calcium supplementation prevents progression to severe disease in preterm nulliparous women with mild preeclampsia. METHODS: Seventy-five women hospitalized at 24-36 weeks' gestation because of mild preeclampsia were randomized to receive either 2 g/day of elemental calcium (36 women) or placebo (39). Both groups had similar demographic characteristics, initial blood pressure measurements, and amount of proteinuria. Diagnostic criteria and clinical management for severe preeclampsia were applied consistently. RESULTS: Eighteen of 36 calcium-treated subjects (50%, 95% confidence interval [CI] 33-67) developed severe preeclampsia, compared with 19 of 39 (48.7%, 95% CI 32-65) in the placebo group (relative risk 1.03, 95% CI 0.64-1.03; P = 1.00). Blood pressure values, gestational age at delivery, newborn weights, incidence of low Apgar scores, and umbilical arterial blood gases were similar for the two groups. CONCLUSION: Calcium supplementation does not prevent severe preeclampsia in preterm patients with mild disease.