Prenatal exposure to persistent organic pollutants (POPs) is correlated with adverse fetal outcomes, but the exact effect across ethnicities is not known. This study aims to evaluate the association between maternal plasma POPs in early pregnancy and the effect on fetal growth.

This cohort study included a total of 2,284 low-risk pregnant women. The participants self-identified their race, ethnicity, and behavioral risk factors. The levels of 76 POPs – 44 polychlorinated biphenyls (PCBs), 11 organochlorine pesticides (OCPs), 11 perfluoroalkyl and polyfluoroalkyl substances, 9 polybrominated diphenyl ethers (PBDEs), and 1 polybrominated biphenyl – in early gestation plasma were measured. The primary outcomes of the study were 14 fetal biometrics, including head circumference, femur length, and abdominal circumference.

Of 2,284 women included, 26.5% were white, 25.8% were black, 27.8% were Hispanic, and 19.9% were Asian. The findings suggested that the OCP mixture was inversely associated with most fetal growth measures. Higher exposure to PBDE mixture was associated with reduced femur length and abdominal circumference. Some interactions by fetal sex were also reported, although most of them had no associations with maternal race/ethnicity.

The research concluded that among pregnant women, the mixture of OCPs was negatively associated with fetal growth measures, and PBDEs were associated with reduced abdominal circumference and femur length.