1. Radboud University; Medicine; Joh. Vijghstraat 3, 6524 BN Nijmegen Netherlands
2. University of Auckland; Obstetrics and Gynaecology; FMHS Park Road Grafton Auckland New Zealand 1003
3. Radboud University Nijmegen Medical Centre; Obstetrics & Gynaecology; Postbus 9101 Nijmegen Netherlands 6500 HB
4. Cochrane Menstrual Disorders and Subfertility Group; Obstetrics and Gynaecology; Park Rd Grafton Auckland New Zealand 1003
5. London Community Healthcare; Westside Contraceptive Services; Raymede Clinic, Exmoor St London UK W10 6DZ