1. Department of Obstetrics and Gynecology, Helsingborg Hospital, Institution of Clinical Sciences Malmö, Lund University, Helsingborg, Sweden;
2. Institution of Clinical Sciences Lund, Center for Reproductive Epidemiology, Lund, Sweden;
3. Tornblad Institute, Lund University, Lund, Sweden;
4. Department of Obstetrics and Gynecology, Institution of Clinical Sciences Malmö, Skåne University Hospital, Lund University, Malmö, Sweden