[1] Oslo Univ Hosp, Div Paediat, Rikshosp, Neonatal Intens Care Unit, N-0027 Oslo, Norway
[2] Univ Oslo, Rikshosp, Fac Med, Fac Div, N-0027 Oslo, Norway
[3] Alesund Hosp, Dept Pediat, Neonatal Intens Care Unit, Alesund, Norway
[4] Univ Lund Hosp, Childrens & Youth Hosp, Neonatal Intens Care Unit, S-22185 Lund, Sweden
[5] Skejby Hosp, Dept Pediat, Aarhus, Denmark
[6] Matern Reg Univ, Dept Neonatol, Nancy, France
[7] Akershus Univ Hosp, Neonatal Intens Care Unit, Childrens & Youth Clin, Nordbyhagen, Norway
[8] Aarhus Univ Hosp, Aalborg Hosp, Dept Pediat, Neonatal Intens Care Unit, DK-8000 Aarhus, Denmark