Comparing growth charts demonstrated significant deviations between the interpretation of postnatal growth patterns in very preterm infants

Aim: This study compared postnatal growth patterns calculated using different reference data in a large cohort of very preterm infants.

Methods: The weight, length and head circumference of 551 very preterm infants born in the Tyrol, Austria, between 2003 and 2011, were obtained at birth, discharge and the corrected ages of three, 12 and 24 months. Growth data are presented as Z-scores in relation to four reference populations: LMS growth by Pan et al., Fenton preterm growth charts, the Euro-Growth Study Group and the World Health Organization (WHO) Anthro programme.

Results: We observed significant differences in mean weight Z-scores using the four reference populations, with the WHO data being the highest. The mean head circumference Z-scores also differed significantly at all time points. We observed a pronounced gap in the microcephaly rate, which was 10 times higher at the age of 24 months if the Pan data were used instead of the WHO data.

Conclusion: Our findings revealed significant deviations between the interpretation of postnatal growth depending on the reference data used, with the most striking differences seen in head circumference. The choice of reference data, and particularly the conclusions drawn from the data, must be interpreted with utmost care.