1. PEDEGO Research Unit, Medical Research Center Oulu, University of Oulu, Oulu, Finland
2. School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
3. Department of Obstetrics and Gynecology, Oulu University Hospital, Oulu, Finland
4. Department of Anaesthesia and Intensive Care Medicine, Kuopio University Hospital, Kuopio, Finland