[1] Linkoping Univ, Dept Obstet & Gynecol Norrkoping, Linkoping, Sweden
[2] Uppsala Univ, Dept Womens & Childrens Hlth, Uppsala, Sweden
[3] Linkoping Univ, Dept Hlth Med & Caring Sci, S-58183 Linkoping, Sweden
[4] Jonkoping Univ, Jonkoping Acad Improvement Hlth & Welf, Sch Hlth & Welf, Jonkoping, Sweden
[5] Karolinska Inst, Dept Womens & Childrens Hlth, Stockholm, Sweden