1. Department of General Practice & Elderly Care Medicine, University Medical Center Groningen, University of Groningen, P.O. Box 196, 9700 AD Groningen, The Netherlands
2. Midwifery Academy Amsterdam Groningen, InHolland, 9713 GL Groningen, The Netherlands
3. Midwifery Science, Amsterdam UMC Location Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HZ Amsterdam, The Netherlands
4. Department of Genetics, University Medical Center Groningen, University of Groningen, 9700 AD Groningen, The Netherlands
5. School of Nursing and Midwifery, Western Sydney University, Blacktown, NSW 2148, Australia
6. Department of Psychology, Faculty of Arts, Charles University, 128 08 Prague, Czech Republic