Calcium supplementation for the prevention of pre-eclampsia

To study the effect of calcium supplementation during pregnancy on blood pressure and maternal and neonatal outcomes.

A total of 524 healthy primigravidas with a blood pressure less than 140/90 mm Hg were randomly assigned between the 12th and 25th weeks to receive 2 g of elemental calcium or placebo and were followed-up until delivery.

The incidence of pre-eclampsia was significantly less in the calcium than in the placebo group (4.0% vs 12.0%; odds ratio [OR], 0.31; 95% confidence interval [CI], 0.15-0.63); the mean systolic and diastolic blood pressures at study completion were different in the calcium and placebo group (P=0.007 and P=0.02). The risk for preterm delivery was less in the calcium (7.0%) than in the placebo (12.7%) group (OR, 0.51; 95% CI, 0.28-0.93). The mean baseline calcium intake was 313.83+/-203.25 mg/day (range, 85.71-910.71 mg/day), which is lower than the recommended dietary intake of 1000 mg, and the 24-hour urinary calcium excretion was 130.82+/-67.44 mg/dL (range, 40.5-387 mg/dL).

Calcium supplementation appears to reduce the occurrence of pre-eclampsia and preterm delivery in primigravidas who have a daily dietary calcium intake less than the recommended dietary allowances.