Prenatal phthalate and bisphenol exposure and gestational diabetes mellitus: a birth cohort study in New York City

Context Plasticizers such as bisphenols and phthalates are endocrine-disrupting chemicals and lead to development of metabolic diseases. Objective To examine associations of prenatal exposure to bisphenols and phthalates with metabolic dysfunction. Design This study was nested in the New York university (NYU) Children’s Health and Environment Study, a prospective birth cohort. Setting Participants were recruited at three NYU-affiliated hospitals. Patients or Other Participants Eligible participants were ≥18 years old, <18 weeks pregnant, and had a medically stable pregnancy. Exposures Twelve phthalate metabolites and two bisphenols were measured in early and mid-pregnancy (<18 and 18-25 weeks) urine samples. Bisphenols were summed, and phthalate metabolites were grouped based by molecular weights and relevant parent compounds. Main Outcome Measures Logistic and linear regression models assessed chemicals groups’ associations with Gestational Diabetes Mellitus (GDM), glucose disturbance (including impaired glucose tolerance (IGT)), and blood glucose response to Glucose Challenge Test (GCT), adjusting for sociodemographic and pregnancy-related factors. Results 79 (6.8%) had GDM, 303 (26.1%) had IGT, and blood glucose response to GCT ranged from 22-386 mg/dL. Bisphenol A (BPA) was negatively associated with blood glucose response to GCT (-1.47 [-2.84, -0.10]), while diethylhexyl phthalate (DEHP; 2.67 [0.98, 4.36]) and high molecular weight phthalates (1.94, [0.17, 3.71]) were positively associated with blood glucose response to GCT. DEHP was also linked to glucose disturbance (1.16 [1.02, 1.31]). Conclusions Our findings suggest that phthalate exposure is associated with GDM. Further mechanistic studies are warranted, particularly given the inverse associations with BPA exposure.