1. Department of Obstetrics & Gynecology, University of Helsinki & Helsinki University Hospital, PO Box 140 FI-00029 HUS, Finland
2. University of Helsinki, Biomedicum, Haartmaninkatu 8, 00290 Helsinki, Finland
3. University of Helsinki & Helsinki University Hospital, Administration, PO Box 705 FI-00029 HUS, Finland
4. Department of Public Health, University of Helsinki, PO Box 41, FI-00014 University of Helsinki, Finland
5. University of Helsinki & Helsinki University Hospital, Administration, PO Box 705 FI-00029 HUS, Finland & University of Eastern Finland, Kuopio, Finland
6. External Evaluation Unit, University of Helsinki & Helsinki University Hospital, PO Box 440 FI-00029 HUS, Finland