Prenatal melamine, aromatic amine, and psychosocial stress exposures and their association with gestational diabetes mellitus in a San Francisco pregnancy cohort

BACKGROUND: Research suggests exposure to chemical and non-chemical stressors may increase the risk of pregnancy complications, including gestational diabetes mellitus (GDM). Exposure to melamine and aromatic amines (AAs) is ubiquitous among pregnant people. However, studies investigating the maternal and fetal health effects of prenatal exposure are limited. OBJECTIVES: This cross-sectional study aimed to (1) evaluate relationships between exposure to aromatic amines, melamine and its derivatives, and gestational diabetes in a pregnancy cohort in San Francisco, California, USA, (2) explore if non-chemical stressors modify these relationships, and (3) assess fetal sex differences using stratification. METHODS: We measured 36 AAs, melamine, and three of its derivatives in second-trimester urine samples (n = 607). Financial strain and psychosocial stress were assessed using self-reported questionnaires. GDM status was abstracted from medical records. We used unadjusted and adjusted logistic regression models to calculate the odds of GDM associated with an interquartile range increase in urinary concentrations of melamine and AAs or higher levels of non-chemical stress, overall and stratified by infant sex. Interaction terms between each chemical and non-chemical stressor were used to test for effect modification. RESULTS: Eight analytes were detected in >65% of participants, with 100% detection of melamine and cyanuric acid. Among male infants, summed urinary concentrations of melamine and its analogs and o-Anisidine were associated with increased odds of GDM (OR: 1.08 1.00, 1.17, OR: 1.18 1.03, 1.36, respectively). Higher levels of perceived stress and discrimination were also associated with increased odds of GDM (OR: 1.41 0.73, 2.70, OR: 2.33 1.16, 4.67, respectively). We found limited evidence of interaction between chemical and non-chemical stressors. IMPACT: This study revealed positive associations between melamine and its analogs, some aromatic amines, and gestational diabetes, especially among pregnant women carrying male fetuses. We also found that levels of perceived stress and discrimination were associated with gestational diabetes.