Yogurt consumption during pregnancy and preterm delivery in Mexican women: A prospective analysis of interaction with maternal overweight status.

Preterm delivery is an important cause of perinatal morbidity and mortality, often precipitated by maternal infection or inflammation. Probiotic-containing foods, such as yogurt, may reduce systemic inflammatory responses. We sought to evaluate whether yogurt consumption during pregnancy is associated with decreased preterm delivery. We studied 965 women enrolled at midpregnancy into a clinical trial of prenatal docosahexaenoic acid supplementation in Mexico. Yogurt consumption during the previous 3 months was categorized as ≥5, 2-4, or <2 cups per week. Preterm delivery was defined as delivery of a live infant before 37 weeks gestation. We used logistic regression to evaluate the association between prenatal yogurt consumption and preterm delivery and examined interaction with maternal overweight status. In this population, 25.4%, 34.2%, and 40.4% of women reported consuming ≥5, 2-4, and <2 cups of yogurt per week, respectively. The prevalence of preterm delivery was 8.9%. Differences in preterm delivery were non-significant across maternal yogurt consumption groups; compared with women reporting <2 cups of yogurt per week, those reporting 2-4 cups of yogurt per week had adjusted odds ratio (aOR) for preterm delivery of 0.81 (95% confidence interval, CI [.46, 1.41]), and those reporting ≥5 cups of yogurt per week had aOR of 0.94 (95% CI [.51, 1.72]). The association between maternal yogurt consumption and preterm delivery differed significantly for nonoverweight women compared with overweight women (p for interaction = .01). Compared with nonoverweight women who consumed <2 cups of yogurt per week, nonoverweight women who consumed ≥5 cups of yogurt per week had aOR for preterm delivery of 0.24 (95% CI [.07, .89]). Among overweight women, there was no significant association. In this population, there was no overall association between prenatal yogurt consumption and preterm delivery. However, there was significant interaction with maternal overweight status; among nonoverweight women, higher prenatal yogurt consumption was associated with reduced preterm delivery.