[1] Emory Univ, Childrens Healthcare Atlanta, Dept Pediat, Div Neonatol, Atlanta, GA 30322 USA
[2] Univ Nebraska Med Ctr, Dept Pediat, Div Neonatol, Omaha, NE 68198 USA
[3] Indiana Univ Sch Med, Riley Childrens Hlth, Dept Pediat, Div Neonatal Perinatal Med, Indianapolis, IN 46202 USA
[4] Univ Cincinnati, Cincinnati Childrens Hosp Med Ctr, Perinatal Inst, Coll Med,Div Neonatol, Cincinnati, OH 45229 USA
[5] Univ Missouri, Mercy Kids Childrens Hosp, Sch Med, Dept Pediat,Div Neonatol, Springfield, MO 65212 USA
[6] Univ Cent Florida, Nemours Childrens Hosp, Coll Med, Orlando, FL 32827 USA