1. School of Clinical Medicine Laboratory, University of KwaZulu Natal, Durban, South Africa
2. South African Medical Research Council, Durban, South Africa
3. School of Public Health and Nursing, University of KwaZulu Natal, Durban, South Africa
4. Discipline of Obstetrics and Gynaecology, School of Clinical Medicine, University of KwaZulu Natal, Durban, South Africa