1. Health Center, City of Vantaa, Finland
2. Department of General Practice and Primary Health Care, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
3. Department of Obstetrics and Gynecology, University of Helsinki and Helsinki University and Helsinki University Hospital, Helsinki, Finland
4. Biostatistics consulting, Department of Public Health, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
5. Finnish Institute of Health and Welfare (THL), Helsinki, Finland
6. Karolinska Institute, Stockholm, Sweden
7. Folkhälsan Research Center, Helsinki, Finland