[1] Univ Alabama Birmingham, Dept Obstet & Gynecol, Birmingham, AL 35233 USA
[2] Univ Calif San Diego, San Diego, CA 92103 USA
[3] Kaiser Permanente Calif, San Diego, CA USA
[4] Univ Pittsburgh, Magee Womens Hosp, Pittsburgh, PA 15213 USA
[5] Univ Utah, Salt Lake City, UT USA
[6] Loyola Univ, Maywood, IL 60153 USA
[7] William Beaumont Hosp, Royal Oak, MI 48072 USA
[8] Univ Texas San Antonio, San Antonio, TX USA
[9] Univ Maryland, Baltimore, MD 21201 USA
[10] Univ Texas SW Med Ctr Dallas, Dallas, TX 75390 USA
[11] New England Res Inst, Watertown, MA 02172 USA
[12] Oakwood Hosp, Dearborn, MI USA
[13] NIH, Bethesda, MD 20892 USA
[14] Dartmouth Hitchcock Med Ctr, Lebanon, NH 03766 USA