1. Department of Obstetrics and Gynaecology VU University Medical Center Amsterdam Amsterdam The Netherlands
2. Department of Obstetrics and Gynaecology Academic Medical Center Amsterdam Amsterdam The Netherlands
3. Department of Epidemiology Julius Center University Medical Center Utrecht Utrecht The Netherlands
4. Stanford Prevention Research Center Stanford University Stanford CA USA
5. The Robinson Institute, School of Paediatrics and Reproductive Health University of Adelaide Adelaide Australia
6. Department of Obstetrics Leiden University Medical Center Leiden The Netherlands