OBJECTIVE - To describe growth of prematurely born infants and create a growth chart adequate to assess growth of infants with less than 29 completed weeks of gestation.
STUDY DESIGN - Birth weight, head circumference and length measurements of 7,425 liveborn preterm infants from 1985 to 1997 were retrieved from a longitudinal database maintained by the neonatology division. The 3rd, 5th, 10th, 15th, 25th, 50th, 75th, 85th, 90th, 95th and 97th percentiles of each measurement were determined and used for mathematical modeling.
RESULTS - Birth weight was described with an exponential function while head circumference and length were described with linear functions. A preterm growth chart for the 10th, 50th and 90th percentiles for birth weight, weight growth, head circumference and length was generated.
CONCLUSION - The mathematical models of growth provide smooth representations of the percentiles across gestational ages.