[1] Univ Gothenburg, Inst Clin Sci, Dept Obstet & Gynecol, Sahlgrenska Univ Hosp,Sahlgrenska Acad, S-41685 Gothenburg, Sweden
[2] Univ Gothenburg, Inst Clin Sci, Dept Pediat, Sahlgrenska Univ Hosp,Sahlgrenska Acad, S-41685 Gothenburg, Sweden
[3] Univ Gothenburg, Endocrinol Sect, Dept Med, Sahlgrenska Univ Hosp,Sahlgrenska Acad, S-41685 Gothenburg, Sweden
[4] Lund Univ, Dept Reprod Epidemiol, Tornblad Inst, Inst Clin Sci, S-22100 Lund, Sweden