1. Department of Obstetrics and Gynaecology Maastricht University Medical Centre Maastricht the Netherlands
2. Department of Cardiology Maastricht University Medical Centre Maastricht the Netherlands
3. Department of Clinical Epidemiology and Medical Technology Assessment Maastricht University Medical Centre Maastricht the Netherlands
4. St George's University of London, Molecular and Clinical Sciences Research Institute St George's University Hospitals NHS Foundation Trust London UK