1. Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.
2. Department of Obstetrics and Gynecology, Kanta-Häme Central Hospital, Hämeenlinna, Finland.
3. Faculty of Social Sciences, University of Tampere, Tampere, Finland.
4. Department of Obstetrics and Gynecology, Tampere University Hospital, Tampere, Finland.