1. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology University of North Carolina Chapel Hill NC
2. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology University of South Florida Tampa FL
3. Department of Obstetrics and Gynecology and Reproductive Biology Massachusetts General Hospital and Diagnostic Ultrasound Associates Boston MA
4. Department of Obstetrics and Gynecology Duke University Durham NC
5. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology Wake Forest University Winston‐Salem NC
6. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology The Ohio State University Columbus OH