[1] Karolinska Inst, Dept Womens & Childrens Hlth, Retzius Vag 13 B, S-17177 Solna, Sweden
[2] Karolinska Univ Hosp, Dept Obstet, Stockholm, Sweden
[3] Mid Sweden Univ, Dept Nursing, Sundsvall, Sweden
[4] Uppsala Univ, Dept Womens & Childrens Hlth, Uppsala, Sweden
[5] Univ Gothenburg, Sahlgrenska Acad, Gothenburg, Sweden