Developmental outcome at 12 months corrected age for infants born less than 30 weeks gestation: influence of reduced intrauterine and postnatal growth.

Infants born at less than 30 weeks gestation were prospectively followed to examine the consequences of size at birth and subsequent growth on development in the first year of life. A total of 438 infants were admitted to the intensive care nursery; 53 (12.1%) infants were small for gestational age (SGA). A total of 315 infants survived to discharge; 19 (6%) were SGA. SGA infants were matched with appropriate for gestational age (AGA) infants for sex, GA, incidence of chronic lung disease and head ultrasound at discharge. The high death rate amongst SGA infants was attributable to a combination of extreme prematurity and inappropriate intrauterine growth. There was no difference between SGA and AGA groups for major developmental disability at 1-year corrected age. The effect of subsequent growth on development was examined by comparing children in the cohort above (Appropriate) and below (Small) the 10th percentile for weight at 1 year. Children small at 1 year had a significantly higher rate of major developmental disability at 1 year. Perinatal variables demonstrate that those infants small at 1 year had been of significantly younger GA, lighter BW, had received more ventilator and oxygen therapy. They also had a higher incidence of chronic lung disease. Thus, being born SGA at less than 30 weeks is not of itself associated with increased disability at 1 year when other confounding factors are taken into account. While a causal link has not been established, poor growth in the first year of life does appear to be associated with poorer outcome at 1 year, irrespective of birth status.