[1] Rigshosp, Copenhagen Univ Hosp, Dept Obstet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
[2] Rigshosp, Copenhagen Univ Hosp, Res Unit Womens & Childrens Hlth, Juliane Marie Ctr, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
[3] Univ Copenhagen, Fac Hlth & Med Sci, Dept Clin Med, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
[4] Univ Southern Denmark, Dept Clin Res, Res Unit Gynecol & Obstet, JB Winslows Vej 4, DK-5000 Odense, Denmark
[5] Univ Copenhagen, Dept Publ Hlth, Sect Biostat, Ostre Farimagsgade 5, DK-1353 Copenhagen K, Denmark
[6] Rigshosp, Copenhagen Univ Hosp, Neurobiol Res Unit, Blegdamsvej 9, DK-2100 Copenhagen, Denmark