[1] Univ Alabama Birmingham, Ctr Womens Reprod Hlth, Birmingham, AL 35205 USA
[2] Univ Alabama Birmingham, Dept Biostat, Birmingham, AL USA
[3] Univ Penn, Dept Obstet & Gynecol, Philadelphia, PA USA
[4] Univ Texas Hlth Ctr Houston, Dept Maternal Fetal Med, Houston, TX USA
[5] Columbia Univ, Dept Obstet & Gynecol, New York, NY USA
[6] Duke Univ, Dept Obstet & Gynecol, Raleigh, NC USA
[7] Baylor Coll Med, Dept Obstet & Gynecol, Houston, TX USA
[8] Univ Oklahoma, Dept Obstet & Gynecol, Coll Med, Oklahoma City, OK USA
[9] Indiana Univ Sch Med, Dept Obstet & Gynecol, Indianapolis, IN USA
[10] Univ Utah, Dept Obstet & Gynecol, Salt Lake City, UT USA
[11] Intermt Healthcare, Salt Lake City, UT USA
[12] Ochsner Hlth, Dept Obstet & Gynecol, New Orleans, LA USA
[13] ChristianaCare Ctr Womens & Childrens Hlth Res, Newark, DE USA
[14] Univ Texas Med Branch, Dept Obstet & Gynecol, Galveston, TX USA
[15] St Peters Univ Hosp, Dept Obstet & Gyne col, New Brunswick, NJ USA
[16] Washington Univ, Dept Obstet & Gynecol, Sch Med, St Louis, MO USA
[17] Univ Mississippi, Dept Obstet & Gynecol, Med Ctr, Jackson, MS USA
[18] Univ Pittsburgh, Dept Obstet Gynecol & Reprod Sci, Sch Med, Pittsburgh, PA USA
[19] Ohio State Univ, Dept Obstet & Gynecol, Coll Med, Columbus, OH USA
[20] Rutgers Robert Wood Johnson Med Sch, Dept Obstet Gynecol & Reprod Sci, Brunswick, NJ USA
[21] Med Coll Wisconsin, Dept Obstet & Gynecol, Milwaukee, WI USA
[22] NewYork Presbyterian Weill Cornell Med, Dept Obstet & Gynecol, New York, NY USA
[23] Emory Univ, Dept Obstet & Gynecol, Sch Med, Atlanta, GA USA
[24] Univ Calif San Francisco, Dept Obstet Gynecol & Reprod Sci, San Francisco, CA USA
[25] Stanford Univ, Dept Obstet & Gynecol, Div Maternal Fetal Med, Stanford, CA USA
[26] NIH, Heart Lung & Blood Inst, Bethesda, MD USA
[27] NewYork Presbyterian Hosp, Lang Res Ctr, Queens, NY USA
[28] USA Childrens & Womens Hosp, Mobile, AL USA
[29] Oregon Hlth & Sci Univ, Dept Obstet & Gynecol, Portland, OR USA
[30] Metro Hlth Case Western Univ, Dept Obstet & Gynecol, Cleveland, OH USA
[31] Miami Valley Hosp, Dayton, OH USA
[32] Univ Arkansas Med Sci, Dept Obstet & Gynecol, Little Rock, AR USA
[33] Univ Alabama Birmingham, Dept Med, Birmingham, AL USA
[34] Univ Alabama Birmingham, Dept Obstet & Gynecol, Birmingham, AL USA