1. Department of Obstetrics and Gynaecology; VU University Medical Centre; Amsterdam the Netherlands
2. Department of Pediatric Cardiology; Academic Medical Centre; Emma Children's Hospital; Amsterdam the Netherlands
3. Department of Paediatric Cardiology; Leiden University Medical Centre; Leiden the Netherlands
4. Department of Obstetrics and Gynaecology; Academic Medical Centre; Amsterdam the Netherlands
5. Department of Epidemiology and Biostatistics; VU University Medical Centre; Amsterdam the Netherlands
6. Department of Obstetrics and Gynaecology; Radboud University Medical Centre; Nijmegen the Netherlands
7. Department of Paediatric Cardiology; VU University Medical Centre; Amsterdam the Netherlands
8. Department of Obstetrics and Gynaecology; Leiden University Medical Centre; Leiden the Netherlands