[1] Helsinki Univ Hosp, Dept Obstet & Gynecol, FI-00270 Helsinki, Finland
[2] Univ Helsinki, FI-00270 Helsinki, Finland
[3] Univ Helsinki, Fac Med, Dept Psychol & Logoped, FI-00270 Helsinki, Finland
[4] Oulu Univ Hosp, Clin Med Res Unit, MRC Oulu, FI-90220 Oulu, Finland
[5] Univ Oulu, FI-90220 Oulu, Finland
[6] Finnish Inst Hlth & Welf, Populat Hlth Unit, FI-00300 Helsinki, Finland
[7] Norwegian Univ Sci & Technol, Dept Clin & Mol Med, NO-7491 Trondheim, Norway
[8] Helsinki Univ Hosp, Childrens Hosp, FI-00290 Helsinki, Finland
[9] Univ Helsinki, FI-00290 Helsinki, Finland
[10] Univ Eastern Finland, Dept Clin Chem, FI-70211 Kuopio, Finland
[11] Finnish Natl Inst Hlth & Welf, FI-00300 Helsinki, Finland
[12] Univ Edinburgh, Edinburgh EH8 9YL, Scotland
[13] Helsinki Univ Hosp, Med & Clin Genet, FI-00270 Helsinki, Finland
[14] Univ Helsinki, Inst Mol Med Finland, Helsinki Inst Life Sci, FI-00270 Helsinki, Finland
[15] Tampere Univ Hosp, Dept Obstet & Gynecol, FI-33520 Tampere, Finland
[16] Tampere Univ, Ctr Child Adolescent & Maternal Hlth Res, Fac Med & Hlth Technol, FI-33520 Tampere, Finland
[17] Turku Univ Hosp, Dept Obstet & Gynaecol, FI-20520 Turku, Finland
[18] Univ Turku, FI-20520 Turku, Finland
[19] Helsinki Univ Hosp, Dept Obstet & Gynecol, Biomedicum 2C,PL 705, Helsinki 00029, Finland
[20] Univ Helsinki, Biomedicum 2C,PL 705, Helsinki 00029, Finland