[1] Univ Texas SW Med Ctr Dallas, Dallas, TX 75390 USA
[2] Univ Calif San Francisco, Philip R Lee Inst Hlth Policy Studies, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Dept Obstet Gynecol & Reprod Sci, Bixby Ctr Global Reprod Hlth & Policy, San Francisco, CA USA
[4] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Populat Family & Reprod Hlth, Baltimore, MD USA
[5] Assiut Univ, Fac Med, Womens Hlth Ctr, Dept Obstet & Gynecol, Assiut, Egypt
[6] El Galaa Matern Teaching Hosp, Dept Obstet & Gynecol, Cairo, Egypt
[7] Univ Coll Hosp, Dept Obstet & Gynecol, Ibadan, Nigeria
[8] Katsina Gen Hosp, Dept Obstet & Gynecol, Katsina, Nigeria