1 Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway; Division of Obstetrics and Gynaecology, Oslo University Hospital, Oslo, Norway.
2 Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway; Oslo Centre of Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway.
3 Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway; Department of Gynaecology and Obstetrics, Østfold Hospital Trust, Grålum, Norway.
4 Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway; Department of Gynecology and Obstetrics, Vestre Viken Hospital Trust, Bærum, Norway.
5 Division of Obstetrics and Gynaecology, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway.
6 Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway.
7 Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway. Electronic address: [email protected].