Preterm Infant Growth Tools

Intrauterine growth curves are generally accepted as the best tool for assessing the growth of preterm infants at birth and postnatally up to 50 weeks post menstrual age (PMA).

Fenton Intrauterine Growth Curves

• Reference measures - Weight for gestational age; length for gestational age; head circumference for gestational age
• Reference data
  
  • Weight-for-gestational age based on preterm pooled data from Germany, United States, Canada, Australia, Scotland, and Italy.
  • Length for gestational age and head circumference for gestational age based on preterm pooled data from United States and Italy
  • Post term data – WHO Child Growth Standard curves (Multicentre Growth Reference Study)
• Comments
  
  • Sex specific
  • 3rd to 97th percentiles
  • Preterm portion is descriptive data with curves created from a metanalysis
  • Post term portion is prescriptive data from a combination of cross-sectional national survey data and longitudinal data
• Growth curves
  
  • Girls: Weight, Length, and Head Circumference
  • Boys: Weight, Length, and Head Circumference 

Olsen Intrauterine Growth Curves for 23-41 weeks gestational age

• Reference measures – Weight for age; length for age; head circumference for age; BMI for age
• Reference data – descriptive data from a large sample of US birth data (1998-2006), ethnically representative US births. Since Fenton has updated data to 2013 and has included a revision to smooth the data between preterm and WHO estimates, Fenton curves should be used.
• Comments:
  
  • Only set of intrauterine growth curves with weight-, length-, head circumference-. and BMI-for-age created from using the same data source for all curves
  • Sex-specific
  • 3rd to 97th percentiles
• Growth curves
  
  • Females: Birth weight for Gestational Age
  • Females: Length and Head circumference for Gestational Age
  • Males: Birth weight for Gestational age
  • Males: Length and Head circumference for Gestational Age
• For use with Olsen intrauterine growth curves
  
  • Olsen BMI-for-age curves, for quantifying disproportionate weight for length
    
    • Females: BMI for Gestational Age
    • Males: BMI for Gestational Age
  • Olsen/WHO 39-50 weeks gestational age – updated graphical version
  • Williamson postnatal BMI-for-age data  – the data represent actual growth and remain consistently below the intrauterine curves that represent optimal growth. These are adjunct tools to the intrauterine curves for a complete assessment of growth in preterm infants
    
    • Comparison of Olsen intrauterine and postnatal median BMI growth curves
    • Mean BMI per Day by 3rd, 50th, and 97th Percentiles for Girls 28-31 Weeks GA at Birth
    • Mean BMI per Day by 3rd, 50th, and 97th Percentiles for Boys 28-31 Weeks GA at Birth