Institution: | 1. Departments of Obstetrics/Gynecology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands;2. Departments of Clinical Chemistry, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands;3. Departments of Clinical Epidemiology and Statistics, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands |