1. FHI; Clinical Sciences; P.O. Box 13950 Research Triangle Park North Carolina USA 27709
2. FHI 360; Clinical Sciences; P.O. Box 13950 Research Triangle Park North Carolina USA 27709
3. University of North Carolina School of Medicine; Obstetrics and Gynecology; CB #7570 Chapel Hill North Carolina USA 27599-7570
4. State University of Campinas (UNICAMP); Department of Obstetrics and Gynecology; Caixa Postal 6181 Campinas São Paulo Brazil 13084-971
5. The University of Liverpool; C/o Cochrane Pregnancy and Childbirth Group, Department of Women's and Children's Health; First Floor, Liverpool Women's NHS Foundation Trust Crown Street Liverpool UK L8 7SS