1. 1International Public Health Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom;
2. 2LSE Health, London School of Economics and Political Science, London, United Kingdom;
3. 3Department of Community Health and Primary Care, College of Medicine, University of Lagos, Idi-Araba, Lagos, Nigeria;
4. 4Department of Obstetrics and Gynaecology, College of Medicine of the University of Lagos, Idi-Araba, Lagos, Nigeria