1 Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, 1161 21 Ave. S., R-1217 Medical Center North, Nashville, TN 37232-2521. Electronic address: ronald.alvarez@vumc.org.
2 Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA.
3 Department of Obstetrics and Gynecology, Virginia Commonwealth University School of Medicine, Richmond, VA.
4 Department of Obstetrics and Gynecology, Stony Brook Medicine, Stony Brook, NY.
5 Department of Obstetrics and Gynecology, Tufts Medical Center, Boston, MA.
6 Department of Obstetrics and Gynecology, University of Michigan Medical School, Ann Arbor, MI.