1 Department of Development and Regeneration, Katholieke Universiteit Leuven, Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium.
2 Department of Obstetrics and Gynecology, Skåne University Hospital Malmö, Lund University, Malmö, Sweden.
3 Department of Development and Regeneration, Katholieke Universiteit Leuven, Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium. Electronic address: dirk.timmerman@uzleuven.be.