Neonatal encephalopathy in New Zealand: Demographics and clinical outcome

To establish the incidence of moderate to severe neonatal encephalopathy (NE) in term infants from New Zealand and to document demographic characteristics and neonatal outcomes.

Cases were reported monthly via the New Zealand Paediatric Surveillance Unit (NZPSU). Data were collected from paediatricians for neonatal items and lead maternity carers for pregnancy and birth details. Term neonatal deaths in the Perinatal and Maternal Mortality Review Committee dataset that were because of hypoxia and/or neonatal deaths from hypoxic ischaemic encephalopathy were added to the cases identified via the NZPSU, if they had not previously been ascertained.

For the period January 2010 to December 2012, there were 227 cases, equivalent to a rate of 1.30/1000 term births (95% CI 1.14-1.48). Rates of NE were high in babies of Pacific and Indian mothers but only reached statistical significance for the comparison between Pacific and NZ European. There was also a significant increase in NE rates with increasing deprivation. Resuscitation at birth was initiated for 209 (92.1%) infants with NE. Mechanical ventilation was required, following neonatal unit admission, in 171 (75.3%) infants. Anticonvulsants were used in 157 (69.2%) infants with phenobarbitone (65.6%), phenytoin (14.5%) and benzodiazapines (21.1%), the most common. Cooling was induced in 168 infants (74%) with 145 (86.3%) reported as commenced within a 6-h window.

The rate of NE in New Zealand is consistent with reported international rates. Establishing antecedent factors for NE is an important part of improving care, which may inform strategic efforts to decrease rates of NE.