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Preterm Infant Growth Velocity Calculations: A Systematic Review
Tanis R Fenton1,2, Hilton T Chan3, Aiswarya Madhu3
1Department of Community Health Sciences, Institute of Public Health, Alberta Children's Hospital Research Institute, and tfenton@ucalgary.ca.
Insights
Standardizing preterm infant growth velocity calculations is crucial. Current methods lack consistency, hindering clinical application and research comparisons for infant growth assessment.
Area of Science:
- Neonatalogy
- Pediatric Growth Assessment
- Biostatistics
Background:
- Clinicians utilize diverse methods to evaluate preterm infant growth velocity.
- Assessing growth velocity is essential for monitoring infant development and health outcomes.
Purpose of the Study:
- To determine the numerical methods employed for calculating weight, length, and head circumference growth velocity in preterm infants.
- To identify the common units and approaches used in growth velocity calculations, such as grams/kilogram/day (g/kg/d), grams/day (g/d), centimeters/week (cm/week), and changes in z-scores.
Main Methods:
- A systematic review of studies measuring growth in preterm neonates was conducted using the Medline database.
- Studies published in English, French, German, and Spanish were included, adhering to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.
- Detailed data extraction was performed on 151 studies reporting g/kg/d weight gain velocity.
Main Results:
- Grams/kilogram/day (g/kg/d) was the most frequent method for weight gain velocity (40%), followed by grams/day (g/d) (32%).
- Twenty-nine percent of studies reported changes in z-scores, indicating a shift towards standardized growth charts.
- Significant variability was observed in the starting points and denominators used for g/kg/d calculations, with 62% not reporting the kilogram denominator.
Conclusions:
- The heterogeneity in methodologies for calculating preterm infant growth velocity complicates inter-study comparisons.
- Lack of standardization poses a significant barrier to translating research findings into effective clinical practice for preterm infant care.
- A need exists for standardized protocols to ensure reliable and comparable assessment of infant growth trajectories.
Context:
Clinicians assess the growth of preterm infants and compare growth velocity using a variety of methods.
Objective:
We determined the numerical methods used to describe weight, length, and head circumference growth velocity in preterm infants; these methods include grams/kilogram/day (g/kg/d), grams/day (g/d), centimeters/week (cm/week), and change in z scores.
Data Sources:
A search was conducted in April 2015 of the Medline database by using PubMed for studies that measured growth as a main outcome in preterm neonates between birth and hospital discharge and/or 40 weeks' postmenstrual age. English, French, German, and Spanish articles were included. The systematic review was conducted by using Preferred Reporting Items for Systematic Reviews and Meta-analyses methods.
Study Selection:
Of 1543 located studies, 373 (24%) calculated growth velocity.
Data Extraction:
We conducted detailed extraction of the 151 studies that reported g/kg/d weight gain velocity.
Results:
A variety of methods were used. The most frequently used method to calculate weight gain velocity reported in the 1543 studies was g/kg/d (40%), followed by g/d (32%); 29% reported change in z score relative to an intrauterine or growth chart. In the g/kg/d studies, 39% began g/kg/d calculations at birth/admission, 20% at the start of the study, 10% at full feedings, and 7% after birth weight regained. The kilogram denominator was not reported for 62%. Of the studies that did report the denominators, the majority used an average of the start and end weights as the denominator (36%) followed by exponential methods (23%); less frequently used denominators included birth weight (10%) and an early weight that was not birth weight (16%). Nineteen percent (67 of 355 studies) made conclusions regarding extrauterine growth restriction or postnatal growth failure. Temporal trends in head circumference growth and length gain changed from predominantly cm/wk to predominantly z scores.
Limitations And Conclusions:
The lack of standardization of methods used to calculate preterm infant growth velocity makes comparisons between studies difficult and presents an obstacle to using research results to guide clinical practice.
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