1. Department of Obstetrics and Gynaecology; National University Hospital; Singapore City Singapore
2. Policy Research & Evaluation Division; Ministry of Health; Singapore City Singapore
3. Obstetrics and Gynaecology, Yong Loo Lin School of Medicine; National University of Singapore; Singapore City Singapore
4. Saw Swee Hock School of Public Health; National University of Singapore; Singapore City Singapore
5. Faculty of Medicine; Pediatrics and Epidemiology and Biostatistics; McGill University; Montreal Canada