1. Belgian Branch of the Dutch Cochrane Centre; Kapucijnenvoer 33 blok J bus 7001 3000 Leuven Leuven Belgium
2. University Hospital Ghent; Obstetrics and Gynaecology; De Pintelaan 185 Ghent Belgium
3. University Medical Center; Department of Reproductive Medicine and Gynecology; Heidelberglaan 100 Utrecht Netherlands
4. The University of Adelaide; The Robinson Institute, School of Paediatrics and Reproductive Health; Level 3, Medical School South Building Frome Road Adelaide South Australia Australia SA 5005
5. University Hospital Gasthuisberg; Leuven University Fertility Centre; Herestraat 49 Leuven Belgium 3000