1. From the Maternal Fetal Medicine Division (S.R.), Women and Infants Hospital, Brown University, Providence, RI; the Departments of Medicine, Obstetrics, and Gynecology (S.A.K., S.V.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Mass; the Division of Epidemiology, Statistics and Prevention Research (R.J.L.), National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, Md; and the Department of...