1. Institute of Clinical Sciences, Department of Obstetrics and Gynaecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
2. Department of Obstetrics and Gynaecology, Södra Älvsborg Hospital, Borås, Sweden
3. Department of Obstetrics and Gynaecology, Sahlgrenska University Hospital, Gothenburg, Sweden
4. Department of Medicine/Haematology and Coagulation Disorders, Sahlgrenska University Hospital, Gothenburg, Sweden