Growth of Extremely Preterm Survivors From Birth to 18 Years of Age Compared With Term Controls

Abstract

OBJECTIVES: To determine changes in height, weight, and BMI of extremely preterm (EPT; gestational age <28 completed weeks) survivors from birth to 18 years of age, compared with term controls. METHODS: Birth, discharge, and follow-up at ages 2, 5, 8, and 18 years of consecutive EPT survivors and contemporaneous term controls born in 1991–1992 in Victoria, Australia. Weight, height, and BMI were converted to z scores and compared between groups. Height z scores at age 2 and midparental height z scores were examined as predictors of height z score at age 18 years. RESULTS: Follow-up rates were >90% until 18 years, when 166 (74%) of 225 EPT subjects and 153 (60%) of 253 controls were assessed. EPT subjects had lower weight z scores than controls at birth, with a much greater difference at discharge, which reduced progressively until age 18 years. EPT children were shorter than controls at all ages, and this difference did not alter greatly over time. BMI z scores were lower in EPT children at younger ages, but by age 18 were similar between groups. Height at age 2 was a better predictor of height at age 18 in EPT participants, compared with midparental height. CONCLUSIONS: EPT survivors were substantially lighter than term controls from birth to late adolescence, although the gap in weight steadily decreased over time from a peak at the time of discharge. The height disadvantage in EPT children compared with controls remained constant over time and BMI scores were similar at age 18 years.