1. Department of Gynecologic Surgery and Obstetrics, Walter Reed National Military Medical Center , Bethesda, MD 20814, USA
2. Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda, MD 20814, USA
3. School of Medicine, Uniformed Services University , Bethesda, MD 20814, USA
4. Department of Military and Emergency Medicine, Uniformed Services University , Bethesda, MD 20814, USA