1. University of the Witwatersrand; Wits Reproductive Health & HIV Institute (WRHI), Faculty of Health Sciences; PO Box 18512 Hillbrow Johannesburg South Africa 2038
2. South African Cochrane Centre, Medical Research Council of South Africa; Cape Town South Africa
3. Stellenbosch University; Faculty of Health Sciences; PO Box 19063 Tygerberg South Africa 7505
4. Medical Research Council of South Africa; South African Cochrane Centre; Cape Town South Africa