Exposure to persistent organic pollutants (POPs) during fetal development can increase the risk of adverse health effects during childhood. Maternal characteristics and physiological changes during gestation such as gestational weight gain (GWG) may have an influence in the overall burden of POPs in neonates. However, the associations between GWG and POP concentrations are still not well established. The researchers examined the association of GWG with cord serum POPs concentrations after adjusting for pre-pregnancy maternal body mass index (BMI) and other potential determinants of the transfer of POPs into newborns. The GWG values were evaluated after grouping by the reference guidelines of the Institute of Medicine (IOM).