1. Department of Epidemiology and International Health Institute, Brown University School of Public Health, Providence, Rhode Island, USA
2. Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town
3. Department of Obstetrics & Gynaecology, University of Cape Town and New Somerset Hospital
4. Chronic Disease Initiative for Africa, Department of Medicine
5. Health through Physical Activity, Lifestyle and Sport Research Centre, Division of Physiological Sciences, Department of Human Biology, University of Cape Town
6. Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa
7. Department of Obstetrics and Gynecology and Medicine, Warren Alpert School of Medicine, Brown University, Providence, Rhode Island
8. Department of Obstetrics and Gynecology, Tufts University School of Medicine, Boston, Massachusetts, USA.