[1] Univ Alberta, Fac Sci, Edmonton, AB T6G 2R3, Canada
[2] Royal Alexandra Hosp, Ctr Studies Asphyxia & Resuscitat, Neonatal Res Unit, Edmonton, AB T6G 2R3, Canada
[3] Univ New South Wales, Sch Womens & Childrens Hlth, Kensington, NSW 2031, Australia
[4] Univ New South Wales, Fac Med, Kensington, NSW 2033, Australia
[5] Univ New South Wales, Sch Womens & Childrens Hlth, Kensington, NSW 2033, Australia
[6] Univ Alberta, Dept Pediat, Edmonton, AB T6G 2R3, Canada