Outcomes of very-low-birthweight infants at 3 years of age born in 2003-2004 in Japan

Pediatr Int. 2011 Dec;53(6):1051-8. doi: 10.1111/j.1442-200X.2011.03480.x. Epub 2011 Nov 14.


Background: The aim of this study was to describe and compare neurodevelopmental outcomes with birthweight (BW) groups at 250-g intervals of very-low-birthweight (VLBW) infants at 3 years of age in a multicenter cohort in Japan.

Methods: A total of 3104 VLBW infants born in 2003 and 2004 registered in a NICU-network database were followed in the study. Neurodevelopmental impairment (NDI) was defined as any of the following impairments: cerebral palsy, unilateral or bilateral blindness, severe hearing impairment, or developmental delay; a developmental quotient (DQ) <70 measured using the Kyoto Scale of Psychological Development test or judged by physicians in infants without the test.

Results: A total of 257 infants died and follow-up data were obtained from 1826 infants. Of the 1826 infants, 155 (8.5%) had cerebral palsy, 25 (1.4%) had visual impairment, and 12 (0.7%) had hearing impairment. Of the 1197 infants in whom DQ was measured, 184 (15.4%) had DQ < 70. The proportion of NDI in the evaluated infants was 19.2% (n= 350), ranging from 11.9% (BW 1251-1500 g) to 42.0% (BW ≤ 500 g). Odds ratios (95%CI) of NDI or death against the group BW 1251-1500 g were 20.62 (13.29-31.97) in BW ≤ 500 g, 7.25 (5.45-9.64) in BW 501-750 g, 2.85 (2.12-3.82) in BW 751-1000 g and 1.18 (0.85-1.64) in BW 1001-1250 g.

Conclusion: The increasing proportion of NDI or death, an indicator of adverse outcome, was associated with decrement in the BW of the groups. Although we have to consider a bias due to loss of follow-up data, the incidence of NDI was similar to previous overseas cohort studies despite the higher survival proportion in our study.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Birth Weight
  • Cause of Death / trends
  • Child Development*
  • Child, Preschool
  • Developmental Disabilities / epidemiology*
  • Developmental Disabilities / etiology
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Infant
  • Infant Mortality / trends
  • Infant, Newborn
  • Infant, Very Low Birth Weight*
  • Intensive Care Units, Neonatal
  • Japan / epidemiology
  • Male
  • Odds Ratio
  • Prognosis
  • Retrospective Studies