[1] Karolinska Univ Hosp, Karolinska Inst, Dept Womens & Childrens Hlth, Div Obstet & Gynaecol, S-17176 Stockholm, Sweden
[2] Gynmed Clin, A-1150 Vienna, Austria
[3] Karolinska Univ Hosp, Karolinska Inst, Dept Med, Clin Epidemiol Unit, S-17176 Stockholm, Sweden