1. Department. Obstetrics and Gynecology, Ziekenhuis Oost-Limburg, Genk, Belgium
2. Department. Physiology, Hasselt University, Diepenbeek, Belgium
3. I-BioStat, Hasselt University, Diepenbeek, Belgium
4. I-BioStat, Catholic University of Leuven, Leuven, Belgium