Growth of Extremely Low Birth Weight Infants (ELBW) born at a Tertiary Hospital: Statural catch-up growth continues during the 3rd year of life

Background: Extremely low birth weight (ELBW) infants, with birth weights less than 1000 g, often experience challenges in postnatal growth. This study aimed to assess the growth patterns of ELBW infants over a 3-year period, focusing on statural catch-up growth. Methods: Anthropometric measures (z-scores) were obtained at birth, 2, 4, 6, 12, 18, 24, and 36 months for 87 ELBW infants born between September 2016 and September 2018. Their growth data was compared to WHO growth standards without adjusting for gestational age. All preterm infants received preterm formula for an average of 4-6 months. Results: ELBW infants showed significant catch-up growth in weight-for-age (WAZ) and length-for-age (LAZ) during the first two years of life, while weight-for-length (WLZ) showed an initial increase followed by a mild decline. By age 3, a substantial proportion of infants achieved normal growth parameters. Specifically, 78% had normal WAZ, 90% had normal LAZ, 87% had normal WLZ, and 91.5% had normal head circumference z-scores (HCZ). Overweight was observed in 7.4% of ELBW infants at age 3. Conclusion: ELBW infants fed preterm formula for 4-6 months demonstrated significant catch-up growth during the first 12-18 months of life, with continued catch-up in LAZ during the third year. A high percentage of these infants achieved normal growth parameters by age 3, emphasizing the effectiveness of early interventions in improving postnatal growth in ELBW infants.