From the Department of Obstetrics and Gynecology, Brown University, Providence, RI (B.L.H., D.J.R., D.A.); George Washington University Biostatistics Center, Washington, DC (R.G.C., L.M.F.); the University of Texas Medical Branch, Galveston (G.R.S.), the University of Texas Health Science Center at Houston, Children's Memorial Hermann Hospital, Houston (S.P.C.), and the University of Texas Southwestern Medical Center, Dallas (B.M.C.); Northwestern University, Chicago (M.J.D., G.M.); Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD (U.M.R.); Columbia University, New York (C.G.-B.); the University of Utah Health Sciences Center, Salt Lake City (M.W.V.); the University of North Carolina at Chapel Hill, Chapel Hill (W.H.G.), and Duke University, Durham (G.K.S.) - both in North Carolina; the Department of Pediatrics (R.P.), University of Alabama at Birmingham (A.T.N.T.), Birmingham; Ohio State University, Columbus (M.M.C.), the University of Colorado School of Medicine, Anschutz Medical Campus, Aurora (R.S.G.); Case Western Reserve University, Cleveland (E.K.C.); Stanford University, Stanford, CA (Y.Y.E.-S.); the University of Pennsylvania, Philadelphia (S.P.), and the University of Pittsburgh, Pittsburgh (H.N.S.); Madigan Army Medical Center, Joint Base Lewis-McChord, WA (P.G.N.); and Washington University, St. Louis (G.A.M.).