1. Department of Obstetrics and Gynecology Satasairaala Central Hospital, Satakunta Hospital District Pori Finland
2. Department of Obstetrics and Gynecology University of Turku Turku Finland
3. Department of Obstetrics and Gynecology Turku University Hospital Turku Finland
4. Occupational Healthcare Center, Mehiläinen Rauma Finland
5. Department of Health Promotion Metropolia University of Applied Sciences Helsinki Finland
6. Department of Biostatistics University of Turku Turku Finland