Averting Gestational Hypertension

Preeclampsia is a serious cause of maternal morbidity and mortality, particularly in low-resource settings. To summarize global data about the effects of prenatal calcium supplements on gestational hypertension and associated morbidity, Cochrane reviewers conducted a meta-analysis of 13 high-quality trials including a total of 15,730 women. In most studies, supplements were begun at 20 weeks' gestation.

The number needed to treat (NNT) with calcium supplements (>1 g daily) to prevent 1 case of preeclampsia was 28, and the NNT to prevent 1 preterm birth was 40. Calcium supplements lowered risk for gestational hypertension by 35%, with the greatest effects among women with low-calcium diets and those at high risk for preeclampsia.