[1] Univ Illinois, Obstet & Gynecol, Chicago, IL USA
[2] Wayne State Univ, Obstet & Gynecol, Detroit, MI USA
[3] Columbia Univ, Obstet & Gynecol, New York, NY USA
[4] Westat Corp, Rockville, MD USA
[5] IMS Inc, Rockville, MD USA
[6] NCI, Div Canc Epidemiol & Genet, Bethesda, MD 20892 USA
[7] Stanford Univ, Dept Obstet & Gynecol, Stanford, CA 94305 USA