[1] Karolinska Inst, Karolinska Univ Hosp, Dept Womens & Childrens Hlth, WHO Ctr, C1 05, S-17176 Stockholm, Sweden
[2] Oregon Hlth & Sci Univ, Dept Obstet & Gynecol, Portland, OR 97201 USA
[3] Univ Estadual Campinas, Dept Obstet & Gynecol, Fac Med Sci, Campinas, SP, Brazil
[4] Clare Pk Hosp, Farnham, Surrey, England
[5] Univ Naples Federico II, Sch Med, Dept Publ Hlth, Naples, Italy