1. WHO Collaborating Centre, Division of Neonatology, Obstetrics, Gynecology, and Reproductive Health, Department of Women’s and Children’s Health, Karolinska University Hospital, Karolinska Institutet, SE 17176 Stockholm, Sweden
2. Department of Obstetrics and Gynecology, Research Unit of Clinical Medicine, Medical Research Centre, Oulu University Hospital, University of Oulu, 90220 Oulu, Finland