Abstract
The objective of this systematic review and meta-analysis is to investigate the effects of vitamin E supplementation on maternal and neonatal vitamin E status. Studies were systematically searched in PubMed, Scopus, Web of Science, EMBASE, LILACS, and the Cochrane Library. Randomized controlled trials (RCTs) comparing vitamin E supplementation in pregnant women with placebo were included. Study selection, data extraction, and risk of bias assessment using the Cochrane Risk of Bias tool were independently performed by reviewers. Meta-analyses were conducted using RevMan 5.4, and the certainty of evidence was assessed using the GRADE approach. Six RCTs including 3.823 pregnant women met the inclusion criteria. Vitamin E supplementation significantly increased maternal serum α-TOH concentrations (SMD = 4.89; 95% CI: 2.89-6.89; p < 0.001), although substantial heterogeneity was observed (I (2) = 99%). Maternal serum levels of vitamin E were measured at baseline and postpartum. No significant effects were found for gestational age at birth (SMD = 0.04 weeks; 95% CI: -0.03 to 0.11; I (2) = 0%; p = 0.29) or birth weight (SMD = -0.02 g; 95% CI: -0.09 to 0.04; I (2) = 62%; p = 0.49). Overall, the studies showed a low risk of bias, with evidence certainty ranging from low to moderate. Meta-analysis results indicate that vitamin E supplementation during pregnancy increases maternal α-TOH levels but shows no consistent clinical benefits for neonatal outcomes. Evidence is limited and heterogeneous, highlighting the need for well-designed trials to clarify its role.