1. Duke-NUS Medical School , Singapore , Singapore
2. Department of Haematology , Singapore General Hospital , Singapore , Singapore
3. Department of Obstetrics and Gynaecology , Singapore General Hospital , Singapore , Singapore
4. Department of Obstetrics and Gynaecology , KK Women’s and Children’s Hospital , Singapore , Singapore
5. Yong Loo Lin School of Medicine , National University of Singapore , Singapore , Singapore
6. Department of Epidemiology , Singapore General Hospital , Singapore , Singapore