[1] Duke Univ Hlth Syst, Duke Hlth Technol Solut, Durham, NC USA
[2] Brigham & Womens Hosp, Dept Obstet & Gynecol, 75 Francis St, Boston, MA 02115 USA
[3] Duke Univ, Sch Med, Dept Obstet & Gynecol, Durham, NC USA
[4] Duke Univ, Dept Med, Durham, NC USA
[5] Duke Univ, Sch Med, Dept Biostat & Bioinformat, 2424 Erwin Rd,Suite 11041, Durham, NC 27705 USA
[6] Duke Univ, Dept Pediat, Childrens Hlth & Discovery Initiat, Sch Med, Durham, NC 27706 USA