To help CDC increase understanding of the effectiveness of using maternal tenofovir containing combination drug during the second and third trimesters of pregnancy for the prevention of mother-to-child transmission of HIV and HBV in co-infected mothers.

To investigate how health, environment and lifestyle factors relate to healthy pregnancy and delivery.

To investigate the potential association between phthalates and increased glucose dysregulation during pregnancy and postpartum period.

To measure the levels of phthalates and their association with potential birth outcomes in a population of pregnant women living in Puerto Rico.