Affiliation: | a Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL b Biostatistics Center, George Washington University, Washington, DC c Department of Obstetrics and Gynecology, Ohio State University, Columbus, OH d National Institute of Child Health and Human Development, Bethesda, MD e Departments of Obstetrics and Gynecology at the University of Texas Southwestern Medical Center, Dallas, TX f University of Alabama at Birmingham, Birmingham, AL g University of Chicago, Chicago, IL h University of Utah, Salt Lake City, UT i University of Pittsburgh, Pittsburgh, PA j Wake Forest University, Winston-Salem, NC k Thomas Jefferson University, Philadelphia, PA l Wayne State University, Detroit, MI m University of Cincinnati, Cincinnati, OH, and Columbia University, New York, NY n Brown University, Providence, RI o University of Miami, Miami, FL p University of Tennessee, Memphis, TN q University of Texas at San Antonio, San Antonio, TX r University of North Carolina, Chapel Hill, NC s University of Texas at Houston, Houston, TX t Case Western Reserve University, Cleveland, OH. |