1 Department of Obstetrics and Gynecology, University Hospitals KU Leuven, Leuven, Belgium.
2 Department of Obstetrics and Gynecology, Amsterdam Reproduction and Development Research Institute, Amsterdam University Medical Centers, VUMC, Amsterdam, The Netherlands.
3 Department of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark.
4 Department of Biomedicine and Prevention, Obstetrics and Gynecological Clinic, University of Rome 'Tor Vergata', Rome, Italy.
5 Department of Obstetrics and Gynecology, Skåne University Hospital Malmö, Lund University, Malmö, Sweden.
6 Queen Charlotte's & Chelsea Hospital, Imperial College, London, UK.