Rate of preterm birth in pregnant women with vitamin E treatment: a population-based study

Objective: Vitamin E is frequently used for prevention/treatment of repeated or threatened abortion and threatened preterm delivery in Hungarian pregnant women, though, internationally this old-fashion method is not recommended. Methods: The rate of preterm birth of newborns in pregnant women with high dose (estimated daily dose 450 mg) vitamin E treatment or without this treatment was compared in the population-based large data set of the Hungarian Case-Control Surveillance System of Congenital Abnormalities. Results: Of 38,151 newborns with any defect, 2,287 (6.0%) had mothers with vitamin E treatment. Pregnant women with vitamin E treatment had very high rate of threatened abortion (43.6% vs. 15.4%) and high rate of threatened preterm delivery (27.5% vs. 13.4%) compared to pregnant women without vitamin E treatment. Nevertheless, the gestational age at delivery was 0.2 week longer and rate of preterm births was lower in the newborns of pregnant women with vitamin E treatment (6.6% vs. 9.3%; adjusted OR with 95% CI: 0.71, 0.63-0.84). This preterm preventive effect of vitamin E treatment could not be explained by known confounders, though folic acid/multivitamins also reduced the rate of preterm birth. Conclusion: The study showed nearly 30% reduction in preterm births of pregnant women with vitamin E treatment.