1. Department of Obstetrics and Gynecology, University Hospital Bern, Bern, Switzerland.
2. Laboratory for Prenatal Medicine, Department of Clinical Research, University of Bern, Bern, Switzerland.
3. Graduate School for Biomedical Sciences (GCB), University of Bern, Bern, Switzerland.
4. Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut.