Comparison of Fenton Versus Intergrowth-21 Growth Charts for Preterm Neonates

Abstract

Background: Fenton charts from developed world are commonly used for growth assessment of preterm newborns. Recently prescribed Intergrowth-21 (IG-21) charts look more promising as they include mixed population from economically diverse nations. Objective: We compared IG-21 with Fenton charts for birth size classification and extrauterine growth in preterm infants. Study design: A prospective collection of growth parameters. Participants: Preterm newborns (<37 weeks). Intervention: Weight (W), length (L), and head circumference (HC) were collected at weekly interval during the stay as well as follow-up. Outcomes: Growth of preterm newborns at birth and last follow-up was assessed using Fenton and IG-21 charts. Agreement between Fenton and IG-21 for percentiles and z-scores of growth parameters was assessed using Bland-Altman plot. Results: A total of 301 preterm newborns were enrolled in the study. Mean (standard deviation [SD]) gestational age at birth was 34.08 (1.84) weeks, while at last follow-up (N = 296) it was 37.62 (1.85) weeks. The mean (SD) of birth W, L, and HC were 1889.24 (418.9) g, 44.69 (3.03) cm, and 30.6 (1.84) cm, respectively, while for last follow-up, they were 2114.76 (397.7) g, 47.64 (2.97) cm, and 32.65 (1.7) cm, respectively. The agreement of z-score/percentile between the 2 growth charts was not good for all the anthropometric parameters. Overall, Fenton reported more intrauterine (42.9% vs 36.9%) and extrauterine (92.9% vs 73%) growth restriction as compared to IG-21. Conclusion: The agreement between the 2 charts was poor. More proportions of the preterm population were growth restricted using Fenton charts.