Maternal obesity and gestational diabetes are associated with placental leptin DNA methylation

Objective In this study, we aimed to investigate relationships between maternal prepregnancy obesity and gestational diabetes mellitus and placental leptin DNA methylation. Study Design This study comprises data on 535 mother-infant dyads enrolled in the Rhode Island Child Health Study, a prospective cohort study of healthy term pregnancies. Prepregnancy body mass index was calculated from self-reported anthropometric measures and gestational diabetes mellitus diagnoses gathered from inpatient medical records. DNA methylation of the leptin promoter region was assessed in placental tissue collected at birth using quantitative bisulfite pyrosequencing. Results In a multivariable regression analysis adjusted for confounders, infants exposed to gestational diabetes mellitus had higher placental leptin methylation (β = 1.89, P = .04), as did those demonstrating prepregnancy obesity (β = 1.17, P = .06). Using a structural equations model, we observed that gestational diabetes mellitus is a mediator of the effects of prepregnancy obesity on placental leptin DNA methylation (β = 0.81, 95% confidence interval, 0.27–2.71). Conclusion Our results suggest that the maternal metabolic status before and during pregnancy can alter placental DNA methylation profile at birth and potentially contribute to metabolic programming of obesity and related conditions.