[1] Case Western Reserve Univ, Div Maternal Fetal Med, Dept Obstet & Gynecol, Cleveland, OH 44106 USA
[2] Case Western Reserve Univ, Ctr Hlth Care Res & Policy, MetroHealth Med Ctr, Cleveland, OH 44106 USA
[3] Cedars Sinai Med Ctr, Burns & Allen Res Inst, Los Angeles, CA 90048 USA
[4] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Bethesda, MD USA
[5] Univ Miami, Sch Med, Miami, FL USA
[6] Univ Illinois, Dept Obstet & Gynecol, Sch Med, Chicago, IL 60612 USA
[7] Univ Texas Med Sch Houston, Dept Obstet & Gynecol, Houston, TX USA
[8] Intermt HealthCare, Salt Lake City, UT USA
[9] Baystate Med Ctr, Dept Obstet & Gynecol, Springfield, MA USA
[10] Maimonides Hosp, Dept Obstet & Gynecol, Brooklyn, NY 11219 USA
[11] Summa Hlth Syst, Akron, OH USA
[12] Christiana Care Hlth Syst, Wilmington, DE USA
[13] Indiana Univ Clarian Hlth, Indianapolis, IN USA
[14] MedStar Hlth, Washington, DC USA
[15] Emmes Corp, Rockville, MD USA