Comparison of Fenton 2013 growth curves and Intergrowth-21 growth standards to assess the incidence of intrauterine growth restriction and extrauterine growth restriction in preterm neonates ≤32 weeks.

Background: Close monitoring of growth pattern in preterm neonates is essential to identify any deviations from the normal pattern. But, there is no international consensus regarding how the growth of preterm neonates should be monitored or what constitutes the ideal pattern of growth in these premature infants.

Objective: To compare the incidence of IUGR & EUGR in preterm neonates ≤32 weeks gestational age based on Fenton 2013 growth curves and Intergrowth-21 growth standards.

Design: Retrospective Cohort Study.

Study Site: Tertiary care neonatal unit with nearly 1000 admissions to the neonatal unit.

Participants: All newborns with gestational age ≤32 weeks (230 6/7 days) admitted to the NICU within 24 h of birth over a period of 3 years from 1 January 2015 to 31 December 2017.

Results: Out of 821 neonates born during the study period 603 were included. The mean birth weight, length, and head circumference were 1356.683 ± 335.91 g, 39.244 ± 3.124 cm, and 27.819 ± 1.906 cm, respectively. The mean discharge weight, length, and head circumference were 1550.70 ± 185.122 g, 41.606 ± 2.026 cm, and 29.398 ± 1.221 cm, respectively. The proportion of infants identified as IUGR at birth with respect to weight, length, and head circumference on both the charts was 15.1, 14.4, and 9%, respectively. The proportion of infants identified as EUGR at discharge with respect to weight, length, and head circumference on both the charts was 45.7, 29.8, and 32.3%, respectively.

Conclusion: The proportion of infants identified as IUGR at birth and EUGR at discharge differed on the usage of Intergrowth charts (Birth reference and postnatal) in comparison to Fenton growth charts. The infants identified as IUGR at birth by Intergrowth charts and not by Fenton growth charts had higher incidence of morbidities.