1. Section of Maternal-Fetal Medicine, Obstetrics, Gynecology and Reproductive Sciences; Yale School of Medicine; New Haven CT USA
2. Department of Obstetrics and Gynecology; Baylor College of Medicine; Houston TX USA
3. University of Maryland School of Medicine; Department of Obstetrics, Gynecology and Reproductive Sciences; Baltimore MD USA
4. The Texas Fetal Center, Department of Obstetrics, Gynecology and Reproductive Sciences; University of Texas Health Medical School; Houston TX USA
5. The Children's Hospital of Philadelphia; Center for Fetal Diagnosis and Treatment; Philadelphia PA USA