Affiliation: | 1. Department of Epidemiology, Rollins School of Public Health, Emory University, , Atlanta, GA;2. Department of Obstetrics and Gynaecology, Kuopio University Hospital, , Kuopio, Finland;3. Nordic School of Public Health, , Gothenburg, Sweden;4. School of Medicine, University of Eastern Finland, , Kuopio, Finland;5. National Institute for Health and Welfare (THL), , Helsinki, Finland |