Changing survival and impairment rates at 18–24 months in outborn very low-birth-weight infants: 1984–1987 versus 1980–1983

Outcomes at 18–24 months corrected age of very low-birth-weight infants admitted to our Neonatal Intensive Care Unit in 1984–1987 (period 2) were compared with the outcomes of infants admitted in 1980–1983 (period 1) (total 1357 infants). In the 500–750–g birth-weight subgroup, the survival rate increased from 32 to 54% ( p = 0.002). Rates of moderate and severe impairment at 18–24 months (neurosensory deficit, or Bayley corrected mental developmental index <68) in this subgroup decreased from 41 to 15% ( p = 0.005), and in those without severe impairment, mean mental Bayley scores in periods 1 and 2 were 84 ± 18 and 90 ± 16, respectively (p = 0.20). Analysis after exclusion of small-for-gestational-age infants gave similar results. In the small-for-gestational-age infants of birth weight 500–750 g, the survival rate increased but the impairment rate was unchanged between periods. It is concluded that outcomes improved in 1984–1987 compared with 1980–1983 only for infants with birth weight of 500–750 g.