Background Most preterm infants have birth weights that are average for gestational age but had growth restriction during their postnatal hospitalization, which is the most common morbidity among preterm survivors, and caused a higher risk of later cognitive dysfunction, behavioral problems, and metabolic disease.
Objective To assess the incidence and risk factors for extrauterine growth restriction (EUGR) in preterm infants with gestational age (GA) less than 32 weeks or birth weights (BW) less than 1,500 g at Chiang Mai University Hospital.
Methods A retrospective chart review of preterm infants with GA less than 32 weeks or BW less than 1,500 grams admitted to the NICU and NCCU at Chiang Mai University Hospital between 2017 – 2020. EUGR was diagnosed by the definition of weight less than 10th percentile based on Fenton preterm growth chart for postmenstrual age at 36 weeks. Risk factors were identified and calculated for odd ratio, 95% CI and p value. Multivariate analysis was performed for controlling confounding factors.
Results Among 310 eligible infants, 201 (64.8%) were diagnosed with EUGR. All of 76 SGA infants (100%) were diagnosed EUGR. Risk factors included proven sepsis (OR 3.90, 95%CI 1.004-1.016, p= 0.001), diuretics use (OR 3.62, 95%CI 1.02-1.08, p= 0.001), definite NEC (OR 3.54, 95%CI 1.03-1.12, p= 0.001), hypertension in pregnancy (OR 2.36, 95%CI 1.03-1.12, p= 0.001) and multiple birth (OR 1.85, 95%CI 1.04-1.53, p= 0.016). Risk factors in nutrition issues included longer time to full enteral feeding (OR 1.08, 95%CI 1.28-4.35, p = 0.006), higher GIR started in TPN (OR 1.28, 95%CI 1.11-1.48, p = 0.001), and maximum concentration of fortified milk (OR 1.26, 95%CI 1.04-3.28, p = 0.04). Following multivariate analysis, diuretics (OR 2.62, 95%CI 0.985-6.98, p = 0.05), definite NEC (OR 2.45, 95%CI 1.004-5.99, p = 0.05), hypertension in pregnancy (OR 2.79, 95%CI 1.46-5.33, p = 0.002), and multiple birth (OR 2.29, 95%CI 1.24-4.24, p = 0.008) were found to significantly increase the risk of EUGR.
Conclusions Multiple births, hypertension in pregnancy, diuretic use, and NEC were found to be associated with an increased risk of EUGR in preterm infants with gestational ages less than 32 weeks and birth weights less than 1,500 grams at Chiang Mai University Hospital. Multiple births and hypertension in pregnancy are unpreventable prenatal risk factors. Whereas diuretics and NEC are preventable, this would have a benefit for planning to prevent risk factors during hospitalization.
