1. Leiden University Medical Center; Department of Obstetrics and Gynaecology; PO Box 9600 Leiden Netherlands 2300 RC
2. Leiden University Medical Center; Department of Internal Medicine; PO Box 9600 Leiden Netherlands 2300 RC
3. Catharina Hospital Eindhoven; Department of Gynaecology, Division of Reproductive Medicine; Michelangelolaan 2 Eindhoven Netherlands NL 5623 EJ