Objective: To evaluate the effect of folic acid supplementation during pregnancy on the risk of gestational hypertension/preeclampsia.
Methods: A systematic review and meta-analysis were conducted. Medline, Embase, Scopus, and the Web of Science were searched from inception to December 2014.
Results: 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.
Conclusion: Whether folic acid supplementation in pregnancy can prevent the occurrence of gestational hypertension/preeclampsia remains uncertain.
Keywords: Folic acid; gestational hypertension; preeclampsia; supplementation.