1. Department of Obstetrics and Gynecology, Kalmar County Hospital, Kalmar, Sweden;
2. Department of Clinical Physiology, Kalmar County Hospital, Kalmar, Sweden;
3. Department of Medicine and Health Sciences, University Hospital Linköping, Linköping, Sweden;
4. Department of Obstetrics and Gynecology Linköping University, Linköping, Sweden;
5. Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden