1. Department of Obstetrics and Gynecology, The University of Texas Medical Branch in Galveston, Galveston, Texas.
2. The Center for Interdisciplinary Research in Women's Health, The University of Texas Medical Branch in Galveston, Galveston, Texas.
3. Department of Economics, Sungkyunkwan University, Seoul, Korea.
4. Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas.