Antioxidants for Preventing Preeclampsia: A Systematic Review

Objective. To investigate the efficacy of antioxidants for preventing preeclampsia and other maternal and fetal complications among pregnant women with low, moderate, or high risk of preeclampsia. Methods. We searched MEDLINE, Embase, CENTRAL, mRCT, and other databases, with no language or publication restrictions. Two independent reviewers selected randomized controlled trials that evaluated the use of antioxidants versus placebo and extracted the relevant data. Relative risks (RRs) and 95% confidence intervals (95% CIs) were calculated. The data were compiled through the random effects model. Main Results. Fifteen studies were included (21,012 women and 21,647 fetuses). No statistically significant difference was found between women who received antioxidant treatment and women who received placebo for preeclampsia (RR = 0.92; 95% CI: 0.82–1.04), severe preeclampsia (RR = 1.03; 95% CI: 0.87–1.22), preterm birth (RR = 1.03; 95% CI: 0.94–1.14), and small for gestational age <10th centile (RR = 0.92; 95% CI: 0.80–1.05). Side effects were numerically more frequent in the antioxidants group compared to placebo, but without significant statistical difference (RR = 1.24; 95% CI: 0.85–1.80). Conclusions. The available evidence reviewed does not support the use of antioxidants during pregnancy for the prevention of preeclampsia and other outcomes.