Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, The Ohio State University, Columbus, OH (K.K.V., C.D.L., M.M.C., S.F.T., S.G.G., W.A.G., M.B.L.); and Departments of Medicine and Obstetrics, Gynecology, and Reproductive Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (C.E.P.)