[1] Univ North Carolina Chapel Hill, Chapel Hill, NC USA
[2] Univ Texas Med Branch, Galveston, TX 77555 USA
[3] Med Univ South Carolina, Charleston, SC USA
[4] Baystate Med Ctr, Springfield, MA USA
[5] Ohio State Univ, Columbus, OH 43210 USA
[6] Maricopa Integrated Hlth Syst, Phoenix, AZ USA
[7] Oregon Hlth & Sci Univ, Portland, OR 97201 USA
[8] Intermt Healthcare, Salt Lake City, UT USA
[9] San Diego Perinatal Ctr, San Diego, CA USA
[10] Reg Obstet Consultants, Chattanooga, TN USA
[11] Christiana Care Hlth Syst, Newark, DE USA
[12] Sera Prognost, Salt Lake City, UT USA