[1] Sahlgrens Univ Hosp, Dept Haematol & Coagulat Disorders, S-41345 Gothenburg, Sweden
[2] Narhalsan Primary Care, Dept Antenatal Care, Vastra Gotaland, Sweden
[3] Univ Gothenburg, Sahlgrenska Acad, Dept Obstet & Gynaecol, Inst Clin Sci, Gothenburg, Sweden
[4] Lund Univ, Skane Univ Hosp, Ctr Thrombosis & Haemostasis, Malmo, Sweden