1. Department of Cardiology University Medical Center Groningen, University of Groningen Groningen The Netherlands
2. Department of Obstetrics University Medical Center Groningen, University of Groningen Groningen The Netherlands
3. Department of Obstetrics and Gynecology Amsterdam University Medical Center, VU University Medical Center Amsterdam The Netherlands
4. Department of Obstetrics Ziekenhuis Oost Limburg Genk Belgium
5. Department of Physiology, Faculty of Medicine and Life Sciences Hasselt University Diepenbeek Belgium