[1] Mayo Clin, Dept Obstet & Gynecol, Rochester, MN USA
[2] Mayo Clin, Dept Lab Med & Pathol, Rochester, MN USA
[3] Mayo Clin, Dept Biomed Stat & Informat, Rochester, MN USA
[4] Univ So Calif, Dept Obstet & Gynecol, Los Angeles, CA 90089 USA
[5] Univ So Calif, Dept Surg Pathol, Los Angeles, CA 90089 USA