1. Department of Pathology Beth Israel Deaconess Medical Center and Harvard Medical School Boston Massachusetts USA
2. Division of Maternal Fetal Medicine Beth Israel Deaconess Medical Center and Harvard Medical School Boston Massachusetts USA
3. Department of Pathology and Molecular Medicine Kingston Health Sciences Centre and Queen's University Kingston Ontario Canada
4. Department of Obstetrics and Gynecology, Los Angeles Fetal Surgery University of Southern California Los Angeles California USA
5. Division of Maternal Fetal Medicine Sunnybrook Health Sciences Centre Toronto Ontario Canada
6. Department of Laboratory Medicine and Pathobiology Sunnybrook Health Sciences Centre Toronto Ontario Canada
7. Department of Pathology Virginia Commonwealth University Richmond Virginia USA
8. Division of Maternal Fetal Medicine Boston Children's Hospital Boston Massachusetts USA