1. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, USA;
2. Division of Maternal Fetal Medicine, Baylor College of Medicine, Houston, TX, USA;
3. Department of Obstetrics and Gynecology, Thomas Jefferson University, Philadelphia, PA, USA;
4. Department of Maternal Fetal Medicine, Virginia Hospital Center, Arlington, VA, USA