1. Sydney Medical School, The University of Sydney, Sydney NSW, Australia
2. Australian Centre for Public and Population Health Research, Faculty of Health, University of Technology Sydney, Sydney NSW, Australia
3. Victorian Assisted Reproductive Treatment Authority, Melbourne Vic, Australia
4. School of Public Health and Preventive Medicine, Monash University, Melbourne Vic, Australia
5. Department of Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand