1. Departments of Gastroenterology and
2. Obstetrics and Gynecology, University Hospital St. Radboud, PO Box 9101, 6500 HB Nijmegen, The Netherlands
3. Department of Obstetrics and Gynecology, ‘Nij Smellinghe’ Hospital, PO Box 20200, 9200 DA Drachten, The Netherlands