Extrauterine growth restriction in very preterm infant: etiology, diagnosis, and 2-year follow-up

In very-preterm small-for-gestational-age (SGA) infants, long-term postnatal growth is confused with extrauterine growth restriction (EUGR). We aimed to document EUGR in SGA infants and in non-SGA infants (true-EUGR) and its relationship with fetal, maternal, and neonatal etiological factors. Four hundred seventy-nine very-preterm infants (< 32 weeks) born between 2003 and 2014 and attending the follow-up clinic were included. INTERGROWTH-21st preterm postnatal growth standards in conjunction with WHO Child Growth Standards were used to judge the postnatal growth patterns. EUGR was defined as weight < 10th percentile according to the sex at 36-34 weeks postmenstrual age, usually at discharge. Catch-up was evaluated at 2-2.5 years. Low-weight-for-age (wasting), low-length-for-age (stunting), and low-head-circumference-for-age were diagnosed if the z-scores were below - 2 SD. Logistic regression analysis estimated the association between the risk factors and EUGR, according to the SGA status at birth. Overall, EUGR occurred in 51% at 36-34 postmenstrual weeks and 21% at 2-2.5 years. However, among 411 non-SGA infants, true-EUGR rates were 43% and 15%, respectively. Conclusion: By 2-2.5 years of age, a true-EUGR of 15% can be expected and only the head circumference normalizes in SGA infants. Low birth weight, hyaline membrane disease, bronchopulmonary dysplasia, and male sex were associated with true-EUGR.What is Known:center dot Fetal, neonatal, or postnatal charts have been considered to monitor the postnatal growth of preterm infants.center dot This selection influences the diagnosis of extrauterine growth restriction (EUGR) and the clinical strategies used.What is New:center dot Extrauterine growth restriction (EUGR) in small-for-gestational-age (SGA) infants can not be considered a true EUGR but a postnatal evolution of fetal growth restriction.center dot Preeclampsia, low gestational age, severe neonatal morbidity and male sex are independently associated with EUGR in non-SGA infants (named true-EUGR), which can be expected in 15% of very preterm infants by 2-2.5 years of age.