[1] Emory Univ, Rollins Sch Publ Hlth, Dept Epidemiol, Atlanta, GA 30322 USA
[2] Yale Univ, Sch Med, Dept Obstet & Gynecol & Reprod Med, New Haven, CT USA
[3] Winthrop Univ Hosp, Dept Obstet & Gynecol, Mineola, NY 11501 USA
[4] Winthrop Univ Hosp, Dept Pediat, Mineola, NY 11501 USA
[5] Maternal Fetal Grp PediatriX, Nashville, TN USA
[6] Centennial Womens Hosp, Perinatal Res Ctr, Nashville, TN USA