Division of Women and Baby, Department of Obstetrics, University Medical Centre Utrecht, Utrecht, The Netherlands;2. Division of Women and Baby, Department of Obstetrics, University Medical Centre Utrecht, Utrecht, The Netherlands;3. Department of Experimental Immunohematology, Sanquin Research, Amsterdam and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands;4. Department of Immunohematology Diagnostics, Sanquin Diagnostic Services, Amsterdam, The Netherlands