Affiliation: | 1. Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Center for Women''s Reproductive Health, Columbia University, New York, New York;2. Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California;3. Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Los Angeles, California |