Department of Obstetrics and Gynaecology, University of the Witwatersrand, University of the Witwatersrand, University of the Witwatersrand, University of the Witwatersrand, University of the Witwatersrand, University of the Witwatersrand, University of New South Wales (UNSW) - Kirby Institute, University of New South Wales (UNSW) - Kirby Institute and University of the Witwatersrand - Reproductive Health and HIV Research Unit (RHRU)