[1] Georgia Regents Univ, Dept Obstet & Gynecol, Augusta, GA 30912 USA
[2] Wayne State Univ, Dept Obstet & Gynecol, Detroit, MI USA
[3] Penn State Univ, Dept Obstet & Gynecol, Hershey, PA USA
[4] Univ Penn, Sch Med, Dept Obstet & Gynecol, Philadelphia, PA 19104 USA
[5] Univ Colorado, Dept Obstet & Gynecol, Denver, CO 80202 USA
[6] Univ Texas Hlth Sci Ctr San Antonio, Dept Obstet & Gynecol, San Antonio, TX 78229 USA
[7] Univ Vermont, Dept Obstet & Gynecol, Burlington, VT 05405 USA
[8] Univ Michigan, Dept Obstet & Gynecol, Ann Arbor, MI 48109 USA
[9] Yale Univ, Sch Publ Hlth, Dept Biostat, New Haven, CT USA
[10] Univ Oklahoma, Coll Med, Dept Obstet & Gynecol, Oklahoma City, OK 73190 USA
[11] Stanford Univ, Med Ctr, Stanford, CA 94305 USA
[12] Carolinas Med Ctr, Charlotte, NC 28203 USA
[13] Univ Med & Dent New Jersey, Newark, NJ 07103 USA
[14] Univ Alabama Birmingham, Birmingham, AL 35487 USA
[15] Univ Calif San Francisco, Dept Reprod Endocrinol & Infertil, San Francisco, CA 94143 USA
[16] Univ Virginia, Ctr Res Reprod, Ligand Core Lab, Charlottesville, VA USA
[17] Upstate Univ Hosp, Syracuse, NY USA
[18] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Fertil & Infertil Branch, Rockville, MD USA