1. Division of Maternal Fetal Medicine, Department of Obstetrics Gynecology, & Women's Health Saint Louis University School of Medicine Saint Louis Missouri USA
2. Sidney Kimmel Medical College Thomas Jefferson University Philadelphia Pennsylvania USA
3. Division of Maternal Fetal Medicine, Department of Obstetrics & Gynecology University of Miami Miami Florida USA
4. Section on Human Biochemical Genetics, Medical Genetics Branch National Human Genome Research Institute Bethesda Maryland USA
5. Division of Maternal Fetal Medicine, Department of Obstetrics & Gynecology Thomas Jefferson University Hospital Philadelphia Pennsylvania USA
6. Division of Maternal Fetal Medicine, Department of Obstetrics & Gynecology Eastern Virginia Medical School Norfolk Virginia USA
7. Division of Maternal Fetal Medicine, Department of Gynecology and Obstetrics The Johns Hopkins University School of Medicine Baltimore Maryland USA