to up to 9 different centers. The two major collaborative activities of the centers have been case-control studies called the National Birth Defects Prevention Study (NBDPS), which collected data for deliveries between 1997 and 2011, and the Birth Defects Study To Evaluate Pregnancy exposureS (BD-STEPS), which began collecting data for deliveries in 2014 and is ongoing through 2023. To support research assessing risk factors for stillbirths (fetal deaths at 20 or more weeks gestation), a largely understudied pregnancy outcome, a case-control study of risk factors for stillbirth was added to BD-STEPS in 2015. This notice of funding opportunity will continue to support the capacity of BD-STEPS to identify novel epidemiologic and genetic risk factors for major, structural birth defects and for stillbirths, and to provide research findings that are intended to be translated into public health prevention messages, as warranted.  Component A (BD-STEPS Core):  Support the epidemiological and genetic birth defect-related research capabilities of BD-STEPS, with a focus on studying: (1) maternal chronic diseases and their treatments; (2) infectious disease in pregnancy; and (3) medications used during pregnancy. Component B (BD-STEPS Stillbirth):  Support the exploration of modifiable risk factors for stillbirths. Component B recipients must apply for and receive concurrent Component A funding. New applicants and current BD-STEPS recipients are encouraged to apply for both components.