1. Department of Obstetrics; Leiden University Medical Centre; Leiden the Netherlands
2. Department of Obstetrics and Gynaecology; Academic Medical Centre; University of Amsterdam; Amsterdam the Netherlands
3. Department of Experimental Immunohaematology; Sanquin Research; Amsterdam the Netherlands
4. Department of General Practice; University Medical Centre; Groningen the Netherlands
5. Centre for Clinical Transfusion Research, Sanquin Research; Department of Clinical Epidemiology; Leiden University Medical Centre; Leiden the Netherlands
6. Leiden University Medical Centre; Department of Translational Immunohematology; Leiden the Netherlands