1. Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
2. Obesity Prevention Program, Department of Ambulatory Care and Prevention, Harvard Medical School/Harvard Pilgrim Health Care, Boston, Massachusetts.
3. Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts.
4. Division of Research, Epidemiology and Prevention Section, Kaiser Permanente, Oakland, California.
5. Connors Center for Women's Health and Gender Biology, Brigham and Women's Hospital, and Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts.