Lifestyle Interventions for Expectant Mothers (LIFE-Moms Phoenix) - Phoenix

Background: \- LIFE-Moms (Lifestyle Interventions for Expectant Moms) is a national project that is studying pregnant women who are overweight or obese. It is looking at ways they can manage their weight gain in pregnancy and how this may affect them and their babies health at birth and through the first year. Researchers want to recruit pregnant women who are being treated at the Phoenix Indian Medical Center. They will participate in a two-part study. Objectives: \- To study pregnant women who are in the LIFE-Moms project at the Phoenix Indian Medical Center. Eligibility: * Pregnant women at least 18 years of age who are overweight or obese. * Participants must be receiving care at the Phoenix Indian Medical Center. * Participants must be having only one child in their pregnancy (no twins or other multiple births). Design: * This study will have two parts. The first part will have three visits to obtain data about health early in pregnancy. It will also let participants and researchers find out if the participants are eligible and should continue in the second part of the study. In the second part, participants will be monitored throughout their pregnancy and during the first year after the baby s birth to test the effects of a lifestyle intervention to control weight gain during pregnancy. * On the Part 1 study visits, participants will have a physical exam and medical history. They will provide blood, urine, hair, and other samples to be examined for possible genetic conditions. * For the Part 2 study visits, participants will be placed in one of two treatment groups. Each group will receive the same prenatal and postnatal care that they would get if they did not join the study. * The first group will have a lifestyle intervention program. They will spend about 2 hours every week with other members of their group to learn diet and activity behaviors that may help with their health. * The second group will have an enhanced care program. They will be given