[1] Hosp Dr Sotero del Rio, Dept Obstet & Gynecol, Ctr Res & Innovat Maternal Fetal Med CIMAF, Santiago, Chile
[2] Pontificia Univ Catolica Chile, Div Obstet & Gynecol, Fac Med, Santiago, Chile
[3] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Perinatol Res Branch, Program Perinatal Res & Obstet, Div Intramural Res,NIH,US Dept HHS, Bethesda, MD USA
[4] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Perinatol Res Branch, Program Perinatal Res & Obstet, Div Intramural Res,NIH,US Dept HHS, Detroit, MI USA
[5] Univ Michigan, Dept Obstet & Gynecol, Ann Arbor, MI 48109 USA
[6] Michigan State Univ, Dept Epidemiol & Biostat, E Lansing, MI 48824 USA
[7] Wayne State Univ, Dept Mol Obstet & Genet, Detroit, MI USA
[8] Wayne State Univ, Sch Med, Dept Obstet & Gynecol, Detroit, MI 48201 USA
[9] Hosp Dr Sotero del Rio, Dept Pathol, Santiago, Chile