1. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology; The George Washington University School of Medicine and Health Sciences; Washington DC USA
2. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology; Sidney Kimmel Medical College at Thomas Jefferson University; Philadelphia PA USA
3. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology; Main Line Health; Wynnewood PA USA