1. Department of Obstetrics and Gynecology; Beth Israel Deaconess Medical Center; Boston Massachusetts USA
2. Department of Obstetrics; Gynecology, and Reproductive Biology, Harvard Medical School; Boston Massachusetts USA
3. Division of Maternal-Fetal Medicine; Beth Israel Deaconess Medical Center; Boston Massachusetts USA
4. Department of Radiology; Advanced Fetal Care Center, Boston Children's Hospital; Boston Massachusetts USA