Incidence of and Risk Factors for Extrauterine Growth Restriction in Preterm Infants with Gestational Age Less Than 32 Weeks or Birth Weight Less Than 1,500 Grams

OBJECTIVE To determine the incidence and risk factors for extrauterine growth restriction (EUGR) in preterm infants with gestational age (GA) less than 32 weeks or birth weight (BW) less than 1,500 grams. METHODS A retrospective cohort study reviewed preterm infants admitted at Chiang Mai University Hospital between January 1, 2017, and December 31, 2020. EUGR was defined as weight below the 10th percentile at 36 weeks postmenstrual age based on the Fenton growth chart. Data were analyzed, with a p-value of less than 0.05 considered statistically significant. Multivariate regression analysis was adjusted for confounding variables. RESULTS Among 310 eligible infants, 201 (64.8%) were diagnosed with EUGR. All of 76 SGA infants (100.0%) were EUGR. Significant risk factors included proven sepsis (OR 3.90, 95%CI 1.13-13.45, p = 0.03), diuretic use (OR 3.62, 95%CI 1.47-8.91, p = 0.005), definite NEC (OR 3.54, 95%CI 1.60-7.83, p = 0.002), maternal gestational hypertension (OR 2.36, 95%CI 1.28-4.35, p = 0.006), and multiple births (OR 1.85, 95%CI 1.04-3.28, p = 0.04). Nutritional risk factors were delayed full enteral feeding (OR 1.08, 95%CI 1.03-1.12, p = 0.001) and higher initial glucose infusion rate (GIR) in TPN (OR 1.28, 95%CI 1.11-1.48, p = 0.001). Infants with EUGR had longer hospital stays and higher hospital costs than non-EUGR infants. Multivariate analysis showed significant risks including definite NEC (OR 2.45, 95%CI 1.01-5.96, p = 0.049), maternal gestational hypertension (adjusted OR 2.79, 95%CI 1.46-5.33, p = 0.002), and multiple births (adjusted OR 2.29, 95%CI 1.24-4.24, p = 0.008). CONCLUSIONS Multiple births, maternal gestational hypertension, SGA status, and NEC were associated with a higher risk of EUGR in preterm infants less than 32 weeks or VLBW. Providing proper antenatal care for mothers with multiple pregnancies or gestational hypertension, along with optimized postnatal care, can help improve growth outcomes and reduce the incidence of EUGR in these infants.