1 Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
2 Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
3 Division of Chronic Disease Research Across the Lifecourse, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts, USA.
4 Department of Reproductive Medicine, KK Women's and Children Hospital, Singapore, Singapore.
5 Duke-NUS Medical School, Singapore, Singapore.
6 Centre for Research in Epidemiology and Statistics, Inserm, Villejuif, France.
7 Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
8 MRC Lifecourse Epidemiology Unit and NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK.
9 Department of Maternal Fetal Medicine, KK Women's and Children's Hospital, Singapore, Singapore.
10 Department of Family Medicine Service, KK Women's and Children's Hospital, Singapore, Singapore.
11 Division of Obstetrics & Gynaecology, KK Women's and Children's Hospital, Singapore, Singapore.
12 Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
13 Department of Paediatrics, KK Women's and Children's Hospital, Singapore, Singapore.
14 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
15 Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore. obgchan@nus.edu.sg.
16 Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. obgchan@nus.edu.sg.