1. Leiden University Medical Center, Department of Obstetrics; Leiden the Netherlands
2. Sanquin Diagnostic Services, Department of Immunohematology Diagnostics; Amsterdam the Netherlands
3. Department of Midwifery Science; Academy of Midwifery Amsterdam-Groningen (AVAG) and the EMGO Institute for Health and Care Research, Vrije Universiteit (VU) Medical Center; Amsterdam the Netherlands
4. Sanquin Research, Department of Donor Studies; Amsterdam the Netherlands
5. Leiden University Medical Center, Department of Immunohematology and Blood Transfusion; Leiden the Netherlands
6. Vrije Universiteit Amsterdam, Department of Sociology; Amsterdam the Netherlands