Dr. Oken's research is focused on the health effects of nutrition and environmental toxicants on health and disease, with a particular focus on pregnancy and early childhood. She has studied the balance of risk and benefit from maternal fish consumption during pregnancy on child development, long term health effects of breastfeeding for both mother and child, and determinants and sequelae of excess gestational weight gain. She has also performed a number of studies on the influence of modifiable behaviors during pregnancy, such as smoking, physical activity, and diet, on risk for obesity among both mothers and their children. Dr. Oken completed residency training in both internal medicine and pediatrics.