Figure 1

Participant recruitment and biological samples collected from pregnant women during mid-gestation at the Women’s Options Center (WOC) in Northern California from 2008–16. We obtained maternal serum samples and questionnaire data from 249 pregnant women undergoing elective terminations during mid-gestation in four study waves from 2008–16: wave 1 (2008–09; n = 25), wave 2 (2011–12; n = 36), wave 3 (2014; n = 50), and wave 4 (2014–16; n = 138). Polybrominated diphenyl ether (PBDE) levels were measured in 247 maternal serum samples. Fetal liver (study waves 2–4; 2014–16; n = 227) and placental tissues (study waves 3–4; 2014–16; n = 191) were also collected in a subset of women. After excluding twins, PBDE measurements were obtained for 180 matched samples of maternal serum, fetal liver, and the placenta in two study waves from 2014–16.