Background and aims Extrauterine growth restriction (EUGR; ≤10th percentile of intrauterine growth expected in accordance with the estimated gestational age) is a common problem in preterm infants. After birth, nutrition in preterm infant is dependent on externally administered nutrition and many preterm infants experience significant energy and nutrition deficits.

We modified our nutrition protocol and evaluated the incidence of EUGR and growth status.

Methods A prospective observational cohort study compared infants ≤1,500 g before (n = 37) and after (n = 50) modification of nutrition protocol. Modification included early starts of macronutrients with higher goal, earlier adding of human milk fortifier and higher goal of daily administered calorie. We evaluated demographics, enteral feeding, growth parameters, laboratory data and discharge outcomes. Differences in subgroups of infants ≤1,000 g and 1,000–1,500 g were also assessed.

Results Modified nutrition protocol reduced the incidence of EUGR at 36 weeks gestational age (GA) (91.8% vs. 66.0%, p = 0.005) and at discharge from NICU (89.1% vs. 56.0%, p = 0.001). EUGR was significantly reduced in infants 1,000–1,500 g and trended toward reduction in infants <1,000 g. Height at 36 weeks GA increased significantly in infants 1,000–1,500 g and head circumference at 36 weeks GA increased significantly in all infants. No significant differences were seen in the rates of NEC, BPD, ROP, IVH and PVL.

Conclusions Modified nutritional protocol based on supplying the early aggressive macronutrients and higher calorie, can significantly reduce the incidence of EUGR in infants ≤1,500 g without any complications. We need further investigation to improve growth in infants <1,000 g.