Comparison of growth patterns in the first year of life between term small for gestational age and appropriate for gestational age South Indian infants

Background Early life growth trajectories of Indian small for gestational age (SGA) infants are sparse. This study aimed to compare longitudinal growth in appropriate for gestational age (AGA) and SGA infants during their first year of life. Methods Apparently healthy term infants (52 SGA, 154 AGA) were recruited at birth and followed up till 1 year. Parental, sociodemographic characteristics and feeding patterns were recorded. Anthropometric measurements were assessed at birth, 3, 6, 9 and 12 months of age; Z scores and growth velocity at 3-month intervals were computed. Longitudinal measurements were compared between the two groups, using the two-way Friedmans test. Median regression with mixed effects was used to adjust covariates; p value <0.05 was considered statistically significant. Result AGA infants had significantly higher median weight (kg) (2.87 (2.67, 3.04) vs 2.39 (2.25, 2.54)) at birth, (7.08 (6.50, 7.54) vs 6.49 (6.13, 6.78)) at 6 months, (8.64 (7.92, 9.14) vs 7.90 (7.36, 8.54)) at 12 months, median length (cm) ((48.10 (47.20, 49.30) vs 46.75 (45.43, 47.50)) at birth, (65.50 (64.23, 66.98) vs 63.33 (62.26, 65.28)) at 6 months, (73.30 (71.58, 74.66) vs 71.55 (70.00, 73.30)) at 12 months. SGA infants had comparable weight velocity at all intervals except 9-12 months (6.62 (6.45, 6.79) vs (6.70 (6.51, 6.85)), being significantly higher than AGA infants. Differences in skinfold thicknesses between groups were observed only at birth. Exclusivity of breast feeding was significantly higher at 3 months in AGA, compared to SGA infants (80.9% vs 57.8%). Length velocity was comparable at all ages between groups. Sexual dimorphism was observed in the growth velocities of both groups. Conclusion SGA infants grew in parallel to AGA infants, having significantly lower anthropometric measurements at all time points. However, growth velocities were similar; SGA infants had significantly higher weight velocity from 9 to 12 months. Longitudinal studies beyond 1 year of age, using body composition are needed to determine the quality of growth in Indian infants.