Organophosphate Ester Exposure in Pregnancy, Gestational Weight Gain, and Postpartum Body Composition in a U.S.-based Longitudinal Pregnancy Cohort

Organophosphate esters (OPEs) are replacement flame retardants that have been implicated as metabolic disruptors and linked to birth size across a number of epidemiologic studies. Little is known about how OPEs impact maternal weight and body composition from pregnancy through the postpartum period. We measured OPE metabolites in mid-pregnancy urine samples from participants in a pregnancy cohort study based in Rochester, NY, USA. We calculated total gestational weight gain (GWG) based on clinical records (n = 278) and additionally measured weight retention and body fat percentage through bioelectric impedance at 6 (n = 205) and 12 months postpartum (n = 167). We fitted adjusted linear and logistic regression models examining OPE concentrations in relation to the outcome measures and secondarily, fitted models stratified by earliest pregnancy BMI (< 25 kg/m2 versus ≥ 25 kg/m2). In main models, most associations were null. Several highly prevalent OPEs such as bis(1,3-dichloro-2-propyl) phosphate (BDCPP; β: -1.02 lbs 95