1. Department of Obstetrics and Gynecology, Maastricht University Medical Centre, Maastricht, The Netherlands
2. Department of Obstetrics and Gynecology, Zuyderland Medical Centre, Sittard-Geleen, The Netherlands
3. Department of Obstetrics and Gynecology, Isala, Zwolle, The Netherlands
4. Central Diagnostic Laboratory, Maastricht University Medical Centre, Maastricht, The Netherlands
5. Department of Epidemiology, Caphri School for Public Health and Primary Care, Maastricht, The Netherlands
6. GROW: School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands