Effect of folic acid supplementation during pregnancy on gestational hypertension/preeclampsia: A systematic review and meta-analysis.

<bold>Objective: </bold>To evaluate the effect of folic acid supplementation during pregnancy on the risk of gestational hypertension/preeclampsia.<bold>Methods: </bold>A systematic review and meta-analysis were conducted. Medline, Embase, Scopus, and the Web of Science were searched from inception to December 2014.<bold>Results: </bold>Out of 1224 potentially relevant studies, 13 studies met our inclusion criteria (2 randomized controlled trials (RCTs), 10 cohort studies, and 1 case-control study). The pooled relative risk (RR) and 95% confidence interval (CI) of the two RCTs were 0.62 (0.45-0.87) in the trial arm as compared with the placebo arm. The pooled RR was 0.92 (95% CI: 0.79-1.08) for nine cohort studies with available data on folic acid supplementation in pregnancy and gestational hypertension/preeclampsia. Pooled RR was 0.88 (95% CI: 0.76-1.02) for eight cohort studies with available data on folic acid supplementation and preeclampsia.<bold>Conclusion: </bold>Whether folic acid supplementation in pregnancy can prevent the occurrence of gestational hypertension/preeclampsia remains uncertain. [ABSTRACT FROM AUTHOR]