[Analysis of the growth trajectories of low birth weight children aged 0 to 4 years based on the superimposition by translation and rotation model].

Authors

B X Zhang, Y Hu, J Y Cui, J Cui, Z J Cui

Published in

Zhonghua er ke za zhi = Chinese journal of pediatrics. Volume 64. Issue 9. Pages 1020-1026. Aug 17, 2026. Epub Aug 17, 2026.

Abstract

Objective: To analyze the growth trajectories of low birth weight children aged 0-4 years in different intrauterine growth status. Methods: A retrospective cohort study was conducted from February 2025 to January 2026 whioh, included 430 low birth weight children who were followed up aged 0-4 years at 15 community health service centers in Xicheng District of Beijing, from January 2018 to December 2022 and had ≥3 follow-up measurements. Children were categorized by gestational age into preterm and term groups, and by intrauterine growth status into small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) groups. Growth trajectories for weight and length (height) were fitted using the superimposition by translation and rotation (SITAR) model based on longitudinal data, and catch-up growth was evaluated using an individual-level cluster resampling method. Results: After excluding 7 preterm SGA children, 423 low birth weight children were included for analysis. Among them, there were 282 children in the preterm SGA group, 74 children in the term AGA group, 67 children in term SGA group, and 218 (51.5%) males. The gestational age of 423 children was (34.9±2.8) weeks, the birth weight was (2.1±0.3) kg,the birth length was (45.2±3.2) cm. There were 6 (4, 7) follow-ups within 4 years of age. Based on the SITAR model fitting results, the weight and height (length) of low birth weight children generally caught up to the P₃ within 2 months of age; the weight reached the P₂₅ at 6.4 months of age in boys and 5.7 months of age in girls, the deceleration of catch-up growth occurred at 19.3 and 14.7 months of age; the height (length) reached the P₂₅ at 10.7 months of age in boys and 9.8 months of age in girls, the deceleration of catch-up growth occurred at 27.7 and 28.3 months of age; stabilizing at the P₂₅-P₅₀ by 48 months of age. The growth rate and trajectory of the preterm AGA group and the term AGA group were similar, the weight reached the P₂₅ at 6.0 and 5.2 months of age in boys and girls, respectively, 6.1 and 6.6 months of age, respectively. Subsequently, the growth rate of the preterm AGA group exceeded that of the term AGA group. Moreover, the height (length) of the preterm AGA group reached the P₂₅ earlier than that of the term AGA group (9.0, 6.4 and 16.1, 9.9 months of age). In the term AGA group and term SGA group, the growth rate and trajectory were similar within the age range of 2.9 to 6.6 months for weight and 4.5 to 16.1 months for length. The age at deceleration of length catch-up growth was earlier in SGA children (25.5 months of age in boys, 30.0 months of age in girls) than in term AGA children (whose length percentile remained below P₂₅ at even 48 months of age). Conclusion: The peaks of catch-up growth for weight and length in low birth weight infants decelerate at 14-20 months for weight and 27-29 months for height, with growth trajectories stabilizing within the P₂₅-P₅₀ range by 4 years of age. Preterm AGA children exhibits more sustained catch-up growth, whereas term SGA children exhibits earlier deceleration but persistent growth deficits.

PMID:
42605086
Bibliographic data and abstract were imported from PubMed on 17 Aug 2026.

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