1. Department of Obstetrics and Gynecology, University of California Los Angeles School of Medicine, Los Angeles, California
2. Department of Obstetrics and Gynecology, University of California San Diego School of Medicine, San Diego, California
3. Department of Obstetrics, Gynecology and Women's Health, University of Minnesota School of Medicine, Minneapolis, Minnesota
4. Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
5. Department of Obstetrics and Gynecology, University of South Florida Morsani College of Medicine, Tampa, Florida
6. Department of Obstetrics and Gynecology, Alpert Medical School of Brown University, Providence, Rhode Island
7. Center for Fetal Medicine and Women's Ultrasound, Los Angeles, California