EFFECT OF CALCIUM SUPPLEMENTATION ON PREGNANCY-INDUCED HYPERTENSION AND PREECLAMPSIA - A METAANALYSIS OF RANDOMIZED CONTROLLED TRIALS

Objective.-To review the effect of calcium supplementation during preg nancy on blood pressure, preeclampsia, and adverse outcomes of pregnan cy. Data Source.-We searched MEDLINE and EMBASE for 1966 to May 1994. We contacted authors of eligible trials to ensure accuracy and complet eness of data and to identify unpublished trials. Study Selection.-Fou rteen randomized trials involving 2459 women were eligible. Data Extra ction.-Reviewers working independently in pairs abstracted data and as sessed validity according to six quality criteria. Data Synthesis.-Eac h trial yielded differences in blood pressure change between calcium s upplementation and control groups that we weighted by the inverse of t he variance. The pooled analysis showed a reduction in systolic blood pressure of -5.40 mm Hg (95% confidence interval [CI], -7.81 to -3.00 mm Hg; P<.001) and in diastolic blood pressure of -3.44 mm Hg (95% CI, -5.20 to -1.68 mm Hg; P<.001). The odds ratio for preeclampsia in wom en with calcium supplementation compared with placebo was 0.38 (95% CI , 0.22 to 0.65). Conclusions.-Calcium supplementation during pregnancy leads to an important reduction in systolic and diastolic blood press ure and preeclampsia. While pregnant women at risk of preeclampsia sho uld consider taking calcium, many more patient events are needed to co nfirm calcium's impact on maternal and fetal morbidity.