[1] Emory Univ, Dept Pediat, Sch Med, Childrens Healthcare Atlanta, Atlanta, GA 30322 USA
[2] RTI Int, Stat & Epidemiol Unit, Res Triangle Pk, NC USA
[3] Univ Iowa, Dept Pediat, Carver Coll Med, Iowa City, IA 52242 USA
[4] Wayne State Univ, Sch Med, Dept Pediat, Detroit, MI 48201 USA
[5] Brown Univ, Women & Infants Hosp, Dept Pediat, Providence, RI 02908 USA
[6] Case Western Reserve Univ, Rainbow Babies & Childrens Hosp, Dept Pediat, Cleveland, OH 44106 USA
[7] Univ Cincinnati, Dept Pediat, Sch Med, Cincinnati, OH 45221 USA
[8] Univ Alabama Birmingham, Sch Med, Div Neonatol, Birmingham, AL USA
[9] Univ Texas Houston, Sch Med, Dept Pediat, Houston, TX USA
[10] Indiana Univ, Sch Med, Dept Pediat, Indianapolis, IN 46202 USA
[11] Univ Calif San Diego, Dept Neonatol, Med Ctr, San Diego, CA 92103 USA
[12] Yale Univ, Sch Med, Dept Pediat, New Haven, CT 06510 USA
[13] Univ Miami, Dept Pediat, Miller Sch Med, Miami, FL 33152 USA
[14] Univ Texas SW Med Ctr Dallas, Dept Pediat, Dallas, TX 75390 USA
[15] Wake Forest Univ, Dept Pediat, Sch Med, Winston Salem, NC 27109 USA
[16] Duke Univ, Dept Pediat, Sch Med, Durham, NC 27706 USA
[17] Stanford Univ, Sch Med, Dept Pediat, Palo Alto, CA 94304 USA
[18] Univ Utah, Sch Med, Dept Pediat, Div Neonatol, Salt Lake City, UT USA
[19] Univ Rochester, Sch Med & Dent, Dept Pediat, Rochester, NY 14642 USA
[20] Floating Hosp Children, Div Newborn Med, Dept Pediat, Tufts Med Ctr, Boston, MA USA
[21] Univ New Mexico, Dept Pediat, Hlth Sci Ctr, Albuquerque, NM 87131 USA
[22] RTI Int, Stat & Epidemiol Unit, Rockville, MD USA
[23] Eunice Kennedy Shriver Natl Inst Child Hlth & Hu, Natl Inst Hlth Bethesda, Bethesda, MD USA