[1] Yale Univ, Yale Women & Childrens Ctr Blood Disorders, Sch Med, Dept Obstet Gynecol & Reprod Sci, New Haven, CT 06520 USA
[2] Bismillah Taqee Inst Hlth Sci & Blood Disorders, Karachi, Pakistan
[3] Dow Univ Hlth Sci & Blood Disorders, Civil Hosp Karachi, Surg Intens Care Unit, Karachi, Pakistan
[4] Dow Univ Hlth Sci, Civil Hosp Karachi, Dept Obstet & Gynecol, Unit 2, Karachi, Pakistan
[5] Dow Univ Hlth Sci, Civil Hosp Karachi, Dept Obstet & Gynecol, Unit 3, Karachi, Pakistan
[6] Dow Univ Hlth Sci, Civil Hosp Karachi, Dept Obstet & Gynecol, Unit 1, Karachi, Pakistan
[7] Bismillah Taqee inst Hlth Sci & Blood Disorders, Karachi, Pakistan
[8] Yale Univ, Sch Med, Yale Ctr Perinatal Pediat & Environm Epidemiol, New Haven, CT USA
[9] Yale Univ, Sch Med, Dept Obstet Gynecol & Reprod Sci, New Haven, CT USA