1. Medical Centre Haaglanden; Department of Gynaecology; Lijnbaan 32 The Hague Netherlands
2. Erasmus Medical Center; Department of Cardiology; PO Box 2040 Rotterdam Netherlands 3000 CA
3. Leiden University Medical Center; Department of Cardiology; PO Box 9600 Leiden Netherlands 2300 RC
4. Leiden University Medical Center; Department of Cardiothoracic Surgery; PO Box 9600 Leiden Netherlands 2300 RC
5. Leiden University Medical Center; Gynaecology, Division of Reproductive Medicine and Dept. of Clinical Epidemiology; PO Box 9600 Albinusdreef 2 Leiden Netherlands NL 2300 RC