1. Department of Obstetrics and Gynecology; Indiana University; Indianapolis; Indiana
2. Department of Obstetrics and Gynecology; Oregon Health and Science University; Portland; Oregon
3. Department of Obstetrics, Gynecology and Reproductive Sciences; University of California; San Francisco; California
4. Vincent Department of Obstetrics and Gynecology; Massachusetts General Hospital; Boston; Massachusetts,; United States of America