Rate of weight gain in very-low birth weight Puerto Rican neonates.

Background: Small for gestational age neonates have a higher risk of growth delay. The purpose of the study is to determine if there are differences in their early weight gain patterns that persist after adjusting for confounding variables.

Methods: Two-hundred sixteen neonates born between 1999 and 2003 were included. The group for analysis was derived by matching all the SGA infants with AGA infants by sex, year of birth, and birth weight. The period of observation was from birth to date of discharge. Weight gain rate was defined as grams gained per kilogram of birth weight per day. Two sample T-test was used to determine the difference in growth rate between the groups. Simple regression was used to establish the effect of morbidities on weight gain rate.

Results: The total mean birth weight was 1105 g (+/- 223 g), the mean gestational age was 30 weeks (+/- 2.7 weeks), and the mean weight gain rate was 13.4 g/kg/d (+/- 6.8 g/kg/d). The mean weight gain rate for the adequate for gestational age group was lower (11.9 g/kg/d +/- 7.6g versus 14.9 g/kg/d +/- 5.5 g) (P < 0.001). When all variables were analyzed using the lineal regression model, only having a low APGAR score (P = 0.02) and being small for gestational age (P = 0.0004) were significant.

Conclusions: We conclude that the growth patterns of very low birth weight neonates are different based on the adequacy of their birth weight, and that the disparity in growth rate is not explained by the differences in the incidence of morbidities that affect growth.