[1] Univ Hosp Ioannina, Dept Obstet & Gynaecol, Ioannina 45100, Greece
[2] Royal Infirm Edinburgh NHS Trust, Simpson Ctr Reprod Hlth, Dept Obstet & Gynaecol, Edinburgh EH16 4S, Midlothian, Scotland
[3] Queen Charlottes & Chelsea Hosp, Hammersmith Hosp, Dept Obstet & Gynaecol, London W12 0HS, England
[4] Cent Lancashire Teaching Hosp, Dept Obstet & Gynaecol, Preston PR2 9HT, Lancs, England
[5] Sci Inst Publ Hlth, Dept Epidemiol, Canc Epidemiol Unit, B-1050 Brussels, Belgium
[6] European Canc Network, IARC, Lyon, France
[7] Coombe Womens Hosp, Dept Gynaecol, Dublin, Ireland
[8] John Radcliffe Hosp, Dept Obstet & Gynaecol, Oxford OX3 9DU, England
[9] Aristotle Univ Thessaloniki, Sch Med, Dept Obstet & Gynaecol 1, GR-54006 Thessaloniki, Greece