The Diabetes & Women?s Health (DWH) study is a study investigating factors (medical, lifestyle, genetic and their interactions) that determine the risk of subsequent development of type 2 diabetes among women who had Gestational Diabetes Mellitus (GDM), a common pregnancy complication. The study is conducted in the US and Denmark among study participants in the Nurses? Health Study II and the Danish National Birth Cohort. The study will investigate pregnancy history, body weight, lifestyle factors (e.g., diet, exercise, and sleep), biochemical markers (in blood, urine, toenails, and saliva) and genetic factors and their interactions in relation to the risk of developing type 2 diabetes and complications such as cardiovascular diseases. Supports Z1AHD008916