Evaluation of postnatal weight growth in very low birth weight infants
Enrico Bertino1, Silvano Milani, Luisa Boni
1Cattedra di Neonatologia, Università di Torino, Turin, Italy. enrico.bertino@unito.it
Insights
Longitudinal studies are crucial for very low birth weight infants (VLBWI) growth assessment. A new mathematical model aids in creating growth charts to identify growth issues in VLBWI, especially those with morbidities.
Area of Science:
- Neonatalogy
- Pediatric Growth and Development
- Biostatistics
Background:
- Accurate growth charts for very low birth weight infants (VLBWI) are lacking.
- Longitudinal studies are essential for monitoring VLBWI postnatal growth.
- Current charts do not adequately detect growth deviations in VLBWI.
Purpose of the Study:
- To analyze the weight growth of 262 VLBWIs from birth to 2 years corrected age.
- To develop and apply a mathematical function for modeling VLBWI growth patterns.
- To generate model-based longitudinal growth charts for VLBWI.
Main Methods:
- Analysis of weight growth data from 262 VLBWIs up to 2 years corrected age.
- Fitting individual growth profiles using a 7-constant exponential-logistic function.
- Comparison of growth trajectories between small-for-gestational-age VLBWIs with and without major morbidities.
Main Results:
- VLBWIs exhibit early and late neonatal peaks in growth velocity.
- Small-for-gestational-age VLBWIs with major morbidities showed significantly reduced weight at 2 years (approx. 860g difference).
- Growth impairment in VLBWIs with morbidities was primarily linked to a reduced late neonatal growth velocity peak.
Conclusions:
- The exponential-logistic function is a valuable tool for creating VLBWI-specific growth charts.
- These model-based charts can aid in early detection of inadequate growth in VLBWI.
- The function can assess the impact of morbidities and care protocols on VLBWI growth kinetics.
Abstract:
There is general agreement about the need for longitudinal studies of very low birth weight infants (VLBWI) to evaluate their postnatal growth and to generate distance and velocity charts that allow neonatologists and pediatricians to detect earlier whether a child is not growing adequately. There are no satisfactory growth charts for VLBWI. We analyzed the weight growth of 262 VLBWIs from birth to 2 years of corrected age. Individual growth profiles were fitted with a 7-constant exponential-logistic function suitable for modelling weight growth pattern. After a postnatal weight loss, all VLBWIs showed a late neonatal peak of velocity between the seventh and 21st weeks; the large majority of them also experienced an early neonatal peak between the second and the sixth weeks. Small-for-gestational-age VLBWIs with major morbidities grew less than reference appropriate-for-gestational-age VLBWIs without major morbidities: at 2 years, the difference in weight was about 860 g. The more severe growth impairment in VLBWIs with major morbidities was almost entirely due to the reduced height of the late neonatal peak of velocity. The mathematical function used in this study is expected to be a useful tool to trace model-based longitudinal distance and velocity charts specific for VLBWIs. Moreover, this function also could be used to evaluate to what extent different pathological conditions or nutritional and medical care protocols affect growth kinetics.
