632 - Updated Reference growth curves for North Indian preterm infants and their comparison with international growth charts

Reference growth charts are used to classify the infant at birth as SGA, AGA, or LGA, thus helping to identify neonates at risk of specific complications. Though both standard and reference charts are in use, the proportion of preterm neonates has been minimal. The present study aimed to establish growth references for Indian preterm infants. Charts from loco-regional population may be better especially in low-middle income countries where the full growth potential has not yet been attained.   

Objective:

To establish reference growth curves for North Indian preterm neonates and to compare them with revised Fenton’s growth charts and the Intergrowth 21st standards.

Design/Methods:

Anthropometry (weight, length, and head circumference) of all eligible preterm (n = 2719) neonates (< 37 weeks) was done prospectively over a period of 14 months. Neonates with congenital infections and anomalies were excluded. Measurements were done as per standard protocols within 18 hours of life. Data on maternal anthropometry, morbidity profile and socio-economic status were collected and mean anthropometric measurements of neonates born to apparently healthy mothers and those with morbidities were analyzed. Growth curves were constructed for both genders for singleton and twin neonates by the LMS method (Lambda, mu and sigma) and compared with other growth curves.

Results:

Out of 14908 births during the study period, 3253 (21%) were born preterm, out of which 2719 neonates could be enrolled, including 414 twin neonates. Baseline characteristics in both twins and singletons were similar, except that twins were born at an earlier gestation (33.0 v 33.7 weeks, p=0.02). Growth curves were constructed by LMS method using the R software. When the growth curves from the present study were used, only 11.3% qualified as SGA, as opposed to the 22.2% when revised Fenton’s charts was used and 29.5% with Intergrowth 21st growth charts. The curves showed that the values for the 50^th centile on the current chart coincided with the Fenton’s charts for gestations 23-27 weeks, while the 50^th centile for weeks 28-31 was between 0 to -0.5Z score of the Fenton’s charts, and between -0.5Z to -1.0Z score for gestational age 32-36 weeks, for both males and females. Mean anthropometric measurements of neonates born to apparently healthy mothers were significantly (p=0.00) higher.

Conclusion(s):

The reference charts derived from the present study can be used for the local preterm population. Use of western growth charts tends to overestimate the incidence of SGA with Intergrowth 21^st charts identifying more SGA infants compared to Fenton charts.