1. Department of Perinatology and Gynaecology, University Medical Centre Utrecht, Utrecht, The Netherlands
2. Laboratory of Psychoneuroimmunology, University Medical Centre Utrecht, Utrecht, The Netherlands
3. Department of Gastroenterology, University Medical Centre, Nijmegen, The Netherlands
4. Department of Obstetrics and Gynaecology, Gelre Ziekenhuizen, Apeldoorn, The Netherlands
5. Department of Obstetrics and Gynaecology, St. Elisabeth Ziekenhuis, The Netherlands