Outcome of outborn infants at the borderline of viability in Western Australia: A retrospective cohort study

J Paediatr Child Health. 2016 Jul;52(7):728-33. doi: 10.1111/jpc.13187. Epub 2016 May 5.


Aim: Preterm infants have a high risk of morbidity and mortality, which increases with decreasing gestational age. Inborn infants (infants born in tertiary perinatal centres) have higher survival and lower morbidity than outborn infants. We aimed to compare short-term and 1-year developmental outcomes of outborn infants at the borderline of viability (≥23 to ≤25 + 6 weeks gestation) with a similar cohort of inborn infants in the sole tertiary perinatal centre in Western Australia from 2001 to 2011.

Methods: This was a retrospective cohort study. Outborn infants ≥23 to ≤25 + 6 weeks gestation who survived to be transported to the Neonatal Intensive Care Unit (NICU) in the perinatal centre were contemporaneously matched to the next inborn infant of comparable gestation and birth weight. We compared mortality, morbidity (including intraventricular haemorrhage, necrotising enterocolitis and chronic lung disease) and Griffiths General Quotient scores at 1-year corrected age.

Results: There were 54 outborn and 519 inborn births in the gestational age range during the study period. Thirty-five (65%) outborn infants were transported to the NICU. Of the outborn infants, 21/54 (39%) survived to discharge compared with 375/519 (72%) inborn infants. For the 35 outborn infants transported to NICU, 14 (40%) died, compared with 6/35 (17%) of inborn infants. There were no differences in short-term and developmental outcomes in surviving infants.

Conclusions: Outborn extremely preterm infants <26 weeks gestation have higher mortality than inborn counterparts. However, those transported to a tertiary NICU have similar morbidity and developmental outcomes.

Keywords: neonatal transport; outborn; preterm infant.

MeSH terms

  • Cohort Studies
  • Gestational Age
  • Humans
  • Infant
  • Infant Mortality
  • Infant, Extremely Premature*
  • Intensive Care Units, Neonatal
  • Morbidity
  • Outcome Assessment, Health Care*
  • Retrospective Studies
  • Transportation of Patients
  • Western Australia