[1] Univ Alabama Birmingham, Div Neonatol, Birmingham, AL 35294 USA
[2] Univ Calif San Diego, San Diego, CA 92103 USA
[3] Case Western Reserve Univ, Rainbow Babies & Childrens Hosp, Dept Pediat, Cleveland, OH 44106 USA
[4] RTI Int, Stat & Epidemiol Unit, Res Triangle Pk, NC USA
[5] Duke Univ, Dept Pediat, Durham, NC 27706 USA
[6] Wake Forest Univ, Sch Med, Winston Salem, NC 27109 USA
[7] Brown Univ, Women & Infants Hosp, Dept Pediat, Providence, RI 02908 USA
[8] Univ Utah, Sch Med, Dept Pediat, Div Neonatol, Salt Lake City, UT USA
[9] RTI Int, Stat & Epidemiol Unit, Rockville, MD USA
[10] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, NIH, Bethesda, MD USA
[11] Univ Cincinnati, Dept Pediat, Cincinnati, OH 45221 USA
[12] Floating Hosp Children, Tufts Med Ctr, Div Newborn Med, Dept Pediat, Boston, MA USA
[13] Univ Texas SW Med Ctr Dallas, Dept Pediat, Dallas, TX 75390 USA
[14] Emory Univ, Sch Med, Dept Pediat, Atlanta, GA USA
[15] Childrens Healthcare Atlanta, Atlanta, GA USA
[16] Univ Texas Med Sch Houston, Dept Pediat, Houston, TX USA
[17] Univ Rochester, Sch Med & Dent, Rochester, NY USA
[18] Indiana Univ Sch Med, Dept Pediat, Indianapolis, IN USA
[19] Stanford Univ, Sch Med, Dept Pediat, Palo Alto, CA 94304 USA
[20] Univ Miami, Miller Sch Med, Miami, FL 33136 USA
[21] Wayne State Univ, Dept Pediat, Detroit, MI 48202 USA
[22] Univ Iowa, Dept Pediat, Iowa City, IA 52242 USA
[23] Yale Univ, Sch Med, Dept Pediat, New Haven, CT 06510 USA
[24] Univ New Mexico, Hlth Sci Ctr, Albuquerque, NM 87131 USA
[25] Univ Chicago, Pritzker Sch Med, Chicago, IL 60637 USA
[26] Rainbow Babies & Childrens Hosp, Cleveland, OH USA
[27] Univ Cincinnati Hosp, Cincinnati, OH USA
[28] Good Samaritan Hosp, Cincinnati, OH USA
[29] Cincinnati Childrens Hosp Med Ctr, Cincinnati, OH USA
[30] Duke Univ, Sch Med, Univ Hosp, Alamance Reg Med Ctr, Durham, NC USA
[31] Durham Reg Hosp, Durham, NC USA
[32] Childrens Healthcare Atlanta, Atlanta, GA USA
[33] Grady Mem Hosp, Atlanta, GA USA
[34] Emory Crawford Long Hosp, Atlanta, GA USA
[35] Indiana Univ Hosp, Indianapolis, IN 46202 USA
[36] Methodist Hosp, Indianapolis, IN USA
[37] Riley Hosp Children, Indianapolis, IN USA
[38] Wishard Hlth Serv, Indianapolis, IN USA
[39] NHLBI, Bethesda, MD 20892 USA
[40] Stanford Univ, Lucile Packard Childrens Hosp, Palo Alto, CA 94304 USA
[41] Floating Hosp Children, Tufts Med Ctr, Boston, MA USA
[42] Univ Alabama Birmingham Hlth Syst, Birmingham, AL USA
[43] Childrens Hosp Alabama, Birmingham, AL USA
[44] Univ Calif San Diego, Med Ctr, San Diego, CA 92103 USA
[45] Sharp Mary Birch Hosp Women, San Diego, CA USA
[46] Univ Iowa Childrens Hosp, Iowa City, IA USA
[47] Univ Miami, Holtz Childrens Hosp, Miami, FL USA
[48] Univ New Mexico, Hlth Sci Ctr, Albuquerque, NM 87131 USA
[49] Univ Rochester, Med Ctr, Golisano Childrens Hosp, Rochester, NY 14642 USA
[50] Univ Texas SW Med Ctr Dallas, Parkland Hlth & Hosp Syst, Dallas, TX 75390 USA