1. Department of Obstetrics; University Medical Centre Utrecht; Utrecht the Netherlands
2. Obstetrical, Perinatal and Paediatric Epidemiology Research Team; Centre for Epidemiology and Statistics Sorbonne Paris Cité; Paris Descartes University; Paris France
3. National Perinatal Epidemiology Unit; University of Oxford; Oxford UK
4. Department of Obstetrics; Rigshospitalet; University of Copenhagen; Copenhagen Denmark
5. Australian Centre for Public and Population Health Research Faculty of Health; University of Technology; Sydney NSW Australia
6. Department of Obstetrics; Leiden University Medical Centre; Leiden the Netherlands