Risk Factors of Extrauterine Growth Restriction in Very Preterm or Very Low Birth Weight Infants

Background: Extrauterine growth restriction (EUGR) is one of the complications that can arise in preterm neonates, impacting future neurodevelopment and growth. Objective: To identify the risk factors of EUGR in very preterm (VPT) or very low birth weight (VLBW) infants. Materials and Methods: A case-control study was conducted at the neonatal intensive care unit (NICU) of Bhumibol Adulyadej Hospital (BAH), Thailand, by reviewing the medical records of VPT or VLBW infants treated at BAH between November 2016 and August 2023. The subjects were divided into EUGR and non-EUGR groups. The primary outcome was the risk factors of EUGR, while the secondary outcome was the characteristics of nutrition support. Results: Data from 78 infants in the present study group and 156 infants in the control group were analyzed. The risk factors for EUGR were bronchopulmonary dysplasia (BPD) (aOR 2.44, 95% CI 1.08 to 5.50, p=0.03) and the time to regain birth weight of more than seven days (aOR 4.83, 95% CI 2.24 to 10.41, p<0.01). The duration of parenteral nutrient support was significantly longer in the study group at 13.5 days for the study group versus 9.0 days for the control group (p<0.01). The time to reach target enteral feeding of 120 mL/kg/day or more was also slower compared to the control group at 15 days for the study group versus 10 days for the control group (p<0.01). Conclusion: BPD and delayed weight regain significantly increase the risk of EUGR. Affected infants require prolonged parenteral nutrition and take longer to reach full oral feeding. To reduce this risk, optimizing nutrition, ensuring adequate protein and energy intake, and improving BPD monitoring with evidence-based respiratory and fluid management are essential for better growth outcomes.