OBJECTIVETo investigate the catch-up growth of preterm infants within a corrected age of 6 months and the risk factors for extrauterine growth retardation (EUGR).

METHODSA total of 321 preterm infants who were discharged after treatment in the neonatal intensive care unit and had regular follow-up documents with complete follow-up records were enrolled. According to the Prenatal Health Care Norms in 2015, these infants were divided into low-risk group with 69 infants and high-risk group with 252 infants. The Z-score method was used to evaluate body weight, body length, and head circumference, and the catch-up growth of the preterm infants within a corrected age of 6 months was analyzed. A multivariate logistic regression analysis was performed to identify the risk factors for EUGR at the corrected age of 6 months.

RESULTSThe percentage of preterm infants with Z scores of body weight, body length, and head circumference of < -2 (not reach the standard for catch-up growth) in both groups decreased gradually with increasing corrected age. At the corrected age of 6 months, the percentages of preterm infants whose body weight, body length, and head circumference did not reach the standard for catch-up growth in the low-risk group were reduced to 1.4% (1/69), 2.9% (2/69), and 1.4% (1/69) respectively, while in the high-risk group, these percentages were reduced to 1.2% (3/252), 1.6% (4/252), and 3.6% (9/252) respectively. The high-risk group had a significantly higher incidence rate of EUGR at the corrected age of 6 months than the low-risk group (28.2% vs 15.9%, P=0.039). The multivariate logistic regression analysis showed that multiple birth (OR=2.68, P=0.010), low birth weight (<1 000 g: OR=14.84, P<0.001; 1 000-1 499 g: OR=2.85, P=0.005), and intrauterine growth retardation (IUGR) (OR=11.41, P<0.001) were risk factors for EUGR at the corrected age of 6 months, while nutritional enhancement after birth (OR=0.25, P<0.001) reduced the risk of EUGR.

CONCLUSIONSMost preterm infants can achieve catch-up growth at the corrected age of 6 months. High-risk preterm infants have a high incidence rate of EUGR at the corrected age of 6 months. Multiple birth, low birth weight, and IUGR are risk factors for EUGR, while rational nutritional enhancement after birth can reduce the incidence rate of EUGR in preterm infants.