1 Chalmers Centre, NHS Lothian, Scotland, United Kingdom. Electronic address: sharon.cameron@ed.ac.uk.
2 Gynmed Clinic, Vienna, Austria; Department of Women's and Children's Health, Division of Obstetrics and Gynaecology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.
3 Department of Women's and Children's Health, Division of Obstetrics and Gynaecology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.