[1] Helsingborg Hosp, Dept Obstet & Gynaecol, Helsingborg, Sweden
[2] Sahlgrens Univ Hosp, Dept Obstet & Gynaecol, Gothenburg, Sweden
[3] Sahlgrens Acad, Inst Clin Sci, Ctr Perinatal Med & Hlth, Gothenburg, Sweden
[4] Skane Univ Hosp Lund, Dept Obstet & Gynaecol, Lund, Sweden
[5] Lund Univ, Dept Clin Sci Lund, Lund, Sweden