[1] Kuopio Univ Hosp, Dept Obstet & Gynecol, POB 100, FI-70029 Kuopio, Finland
[2] Univ Eastern Finland, Sch Med, Inst Clin Med, POB 1627, Kuopio 70211, Finland
[3] Kuopio Univ Hosp, Dept Pediat, POB 100, Kuopio 70029, Finland
[4] Helsinki Univ Hosp, Jorvi Hosp, Dept Med, POB 100, Kuopio 00029, Finland
[5] Univ Eastern Finland, Dept Pediat, POB 1627, Kuopio 70211, Finland
[6] Univ Helsinki, Dept Obstet & Gynecol, Cent Hosp, POB 140, Helsinki 00029, Finland
[7] Univ Helsinki, Dept Obstet & Gynecol, POB 3, Helsinki 00014, Finland