Project Description (Abstract) Flame retardants are chemicals that are applied to materials to prevent the start or slow the growth of fire. Although some of these chemicals, such as polybrominated diphenyl ethers (PBDE’s) have been phased out of production, they remain persistent in the environment. PBDEs do not chemically bind to the products to which they are added, so they easily release from these products and get into the air and dust. Although PBDEs have been phased out of production, some organophosphate flame retardants (OPRFs) and other alternatives have been identified as replacements. Due to this, there is a growing concern on flame retardants and how they can affect maternal and child health during pregnancy. Studies on the effects of flame retardants and birth outcomes are mixed. Flame retardants and other pollutant biomarkers are usually measured through blood and urine samples during pregnancy. This sampling scheme is limited in detecting other persistent environmental pollutants that may also be relevant exposures. To address this limitation, the development of silicone wristbands is a novel approach to measure multipollutant exposures because of its non-invasive and minimally burdensome nature, particularly for pregnant women. Oxidative stress has been implicated in many reproductive and pregnancy disorders, from subfertility to miscarriage, maternal vascular disease and preterm birth4. It has been suggested as a mechanism linking chemical exposure and adverse pregnancy outcomes. To this end, the proposed project will examine the relationship between flame retardants and phthalate biomarkers measured by silicone wristbands and their associations to gestational length and birthweight. It will also be an exploratory analysis of the potential mediation of oxidative stress on this relationship using the New Hampshire Birth Cohort study.