[1] Univ Witwatersrand, Wits Reprod Hlth & HIV Inst, Fac Hlth Sci, Johannesburg, South Africa
[2] Univ Cape Town, Sch Publ Hlth & Family Med, Womens Hlth Res Unit, Fac Hlth Sci, Cape Town, South Africa
[3] UCL, EGA Inst Womens Hlth, London, England
[4] UCL, Inst Global Hlth, London, England
[5] Botswana UPenn Partnership, Gaborone, Botswana
[6] Univ Witwatersrand, Maternal Adolescent & Child Hlth MatCH Res Uni, Dept Obstet & Gynaecol, Fac Hlth Sci, Durban, Kwazulu Natal, South Africa
[7] Univ KwaZulu Natal, Sch Hlth Sci, Durban, South Africa
[8] Univ Witwatersrand, Hlth Econ & Epidemiol Res Off, Dept Internal Med, Sch Clin Med,Fac Hlth Sci, Johannesburg, South Africa
[9] Natl Dept Hlth, Pretoria, South Africa