OBJECTIVE: To evaluate the growth pattern of extremely low birth weight infants(ELBW) from birth to 24 months of adjusted gestational age (AA), the influence of bronchopulmonary dysplasia (BPD) and risk factors associated to growth failure. METHODS: This cohort study included all singleton inborn infants with birthweight <1,000g, admitted in the follow-up clinic of a level III Perinatal Center. Weight, length and head circumference were measured at birth, 40 weeks, and 3, 6, 9, 12, 18, 24 months AA, and Z-scores were calculated. Out of the 82 survivors, 70 were studied and classified in two groups: BPD (n=41) and no-BPD (n=29). Statistical analysis included t-test or Mann-Withney, chi-square or Fisher Exact test, and multivariate logistic regression. RESULTS: In both groups, weight z-score decreased significantly between birth and 40 weeks AA. A peak incremental change in weight, length and head circumference z-scores occurred between 40 weeks and three months. Z-scores for the no-BPD group were close to the expected values by the age of six months and remained at these levels at 24 months AA. Children with BPD had lower z-scores for weight and head circumference in the first year of life, but no difference was found between BPD and no-BPD children in the second year of life. Regression analysis showed that catch-down in weight z-score at 40 weeks was a risk factor for failure to thrive. CONCLUSIONS: ELBW infants experienced early catch-up growth during the first two years of life. ELBW with BPD had poor weight gain. Post-natal growth restriction predicts failure to thrive in infancy.
infant; premature; infant, extremely low birth weight; bronchopulmonary dysplasia; growth
