Growth patterns over 2 years after birth according to birth weight and length percentiles in children born preterm

Purpose: To analyze growth patterns over 2 years after birth according to preterm infant birth weight and length percentiles. Methods: Anthropometric measurements of 82 preterm infants were retrospectively reviewed. Preterm infants with birth weight or length below the 10th percentile were classified as small for gestational age (SGA) (n=19) and those between the 10th and 89th percentile as appropriate for gestational age (AGA) (n=63). The association between the length standard deviation score (SDS) at 2 years of corrected age and clinical factors were analyzed. Results: The length SDS of the SGA group was significantly increased at 6 months (-1.30 +/- 1.71) and 24 months (-0.97 +/- 1.06) of corrected age. The length SDS was lower in the SGA group than those in the AGA group at 6 months (-1.30 +/- 1.71 vs. -0.25 +/- 1.15, P=0.004), 18 months (-0.97 +/- 1.39 vs. -0.03 +/- 1.29, P=0.015), and 24 months (-0.97 +/- 1.06 vs. -0.29 +/- 1.12, P=0.022,). The percentage of children with a length SDS of <-2 (growth failure) at 24 months was 15.8% in the SGA group and 4.8% in the AGA group (P=0.108). Multiple linear regression analysis demonstrated that length at 24 months of corrected age was negatively correlated with birth length below the 10th percentile (coefficient beta=-0.91, P=0.001) and duration of stay in the neonatal intensive care unit (NICU) (coefficient beta=-0.01, P=0.001). Conclusion: Despite the fact that catch-up growth occurs during the early period of infancy in a large portion of preterm SGA infants, a significant portion of these infants show growth failure at 24 months of age. Growth over 2 years after birth is affected by birth length and duration of stay in the NICU in preterm children.