Time to catch-up: postnatal growth trajectories in preterm infants at a tertiary care hospital in Riyadh, Saudi
Mahdi A Alnamnakani1,2, Lana A Shaiba3,4, Adnan Hadid1,5
1Department of Pediatrics, College of Medicine, King Saud University, P.O. Box 12372, Riyadh, Saudi Arabia.
Insights
Preterm infants experience early growth deficits but achieve weight catch-up within the first year. Linear growth recovery takes longer, closer to 24 months corrected age, highlighting the need for monitoring.
Area of Science:
- Pediatric Growth and Development
- Neonatal Medicine
- Public Health
Background:
- Preterm birth is a major global health issue with significant long-term consequences.
- Postnatal growth trajectories are critical for preterm infant outcomes.
- Limited data exist on catch-up growth in Middle Eastern preterm populations.
Purpose of the Study:
- To determine the time required for catch-up weight in preterm infants.
- To characterize postnatal growth trajectories in preterm infants.
- To analyze growth patterns across different birth weight categories in Saudi Arabia.
Main Methods:
- Retrospective cohort study of preterm and term infants.
- Anthropometric measurements collected up to 24 months corrected age.
- Growth analysis using sex-specific Z-scores and linear mixed-effects models.
Main Results:
- Preterm infants showed significantly lower birth weight and length.
- Weight gain was parallel over time, but linear growth trajectories differed.
- Weight-for-age Z-scores converged by 24 months; catch-up growth was highest in very low birth weight infants.
Conclusions:
- Preterm infants exhibit early growth deficits.
- Weight catch-up is achieved within the first year, while linear catch-up extends to 24 months.
- Vigilant monitoring and tailored nutrition are crucial for preterm infants.
Background:
Preterm birth remains a significant global health concern, with long-term outcomes closely linked to postnatal growth trajectories. Data regarding the timing of catch-up growth in preterm infants from Middle Eastern populations are limited. This study aimed to assess the time required to achieve catch-up weight and to characterize postnatal growth trajectories across birth-weight categories at a tertiary care hospital in Riyadh, Saudi Arabia.
Methods:
This retrospective cohort study included 134 preterm infants (< 37 weeks' gestational age) and 193 term infants born between January 2018 and early 2019 at King Saud University Medical City. Anthropometric measurements were recorded at predefined intervals up to 24 months of corrected age. Growth was evaluated using sex-specific Z-scores based on WHO Child Growth Standards. Catch-up growth was defined as a Z-score increase > 0.67 between two consecutive time points. Longitudinal weight and length trajectories were analyzed using linear mixed-effects models with subject-specific random intercepts and a first-order autoregressive covariance structure, with adjusted estimated marginal means derived over time. Reporting followed the STROBE statement for cohort studies.
Results:
Preterm infants had significantly lower birth weight (1.72 ± 0.60 kg vs. 2.97 ± 0.66 kg; p < 0.001) and birth length (40.65 ± 5.36 cm vs. 48.27 ± 3.55 cm; p < 0.001) compared with term infants. In mixed-effects models, preterm infants had lower adjusted weight overall (p = 0.006), but the group-by-age interaction was not significant (p = 0.271), indicating parallel weight gain over time. For length, a significant group-by-age interaction (p < 0.001) indicated that linear-growth trajectories differed between groups, with preterm infants remaining shorter throughout follow-up. Weight-for-age Z-scores converged across birth-weight categories by 24 months. Catch-up growth rates were highest among very low birth weight infants (31.8% by 24 months).
Conclusions:
Preterm infants demonstrate significant early growth deficits with weight catch-up achieved within the first year of corrected age, while linear growth recovery extends closer to 24 months. These findings underscore the importance of vigilant growth monitoring and individualized nutritional strategies during early infancy.
