1. School of Clinical Medicine Research Laboratory, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
2. Department of Obstetrics and Gynaecology, School of Clinical Medicine, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
3. Department of Biostatistics, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
4. School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa