1. Department of Obstetrics and Gynecology; University of Iowa Carver College of Medicine; Iowa City IA 52245 USA
2. Department of Obstetrics and Gynecology; University of Utah School of Medicine; Salt Lake City UT 84132 USA
3. Obstetrics & Gynecology; American College of Obstetricians and Gynecologists; Washington DC 20024-2188 USA