Association Between Atopic Dermatitis in Pregnant Women and Preterm Births: The Japan Environment and Children’s Study

Objectives: This study aimed to evaluate the association between atopic dermatitis in pregnant women and preterm births, accounting for maternal ritodrine hydrochloride administration status. Methods: Data of 83,796 women with singleton pregnancies at and after 22 weeks of gestation (enrolled between 2011 and 2014) were analyzed. These data were obtained from the Japan Environment and Children’s Study. Atopic dermatitis was defined based on self-reported questionnaire responses obtained during the first trimester. The primary outcome measures were preterm births before 37, 32, and 28 weeks of gestation. Using a multivariable logistic regression model, odds ratios for preterm births in pregnant women with atopic dermatitis were calculated, with women without atopic dermatitis included in the reference group. This analysis considered confounding factors and maternal ritodrine hydrochloride administration. Results: Among pregnant women with atopic dermatitis, the adjusted odds ratios (95% confidence intervals) for preterm births before 37, 32, and 28 weeks of gestation were 0.89 (0.81–0.98), 0.98 (0.74–1.30), and 0.88 (0.50–1.55), respectively. This trend remained consistent after excluding participants who received ritodrine hydrochloride. Conclusions for practice: Atopic dermatitis in pregnant women was significantly associated with a decreased incidence of preterm births before 37 weeks of gestation, even after accounting for the effects of maternal ritodrine hydrochloride administration.