Comparison of Body Measurements and Adiposity Between Small and Appropriate for Gestational Age Term Neonates: An Observational Study

Abstract

Background Small for gestational age (SGA) infants have preserved adipose tissue compared to appropriate for gestational age (AGA) infants. This forms the basis of the fetal origin of adult disease. Studies show that Indian babies are ‘thin’ but ‘fat’ compared to babies born in high-income countries. Skin fold thickness (SFT) is a measure of adiposity. Objective To compare the newborn adiposity by SFT in term moderate SGA infants and term AGA infants. Methods We included 222 term newborns, 62 moderate SGA, and 160 AGA with no fetal growth restriction. Babies born to mothers with obesity, abnormal weight gain, pregnancy-related illnesses, and severe SGA were excluded. Weight, length, head circumference, and other circumferences (mid-upper-arm, abdominal, and mid-thigh) and SFT (Anterior abdomen, quadriceps or mid-thigh, triceps, and subscapular) were measured. The mean SD scores were calculated for each of the measurements. Comparisons were made using independent sample t-test. Results Weight, length, circumferences, and SFT were significantly lower ( p < .001) in the SGA infants compared to AGA. Among AGA, the mean standard deviation (SD) scores of all measures ranged between 0.1 and 0.5. However, in the SGA group, the mean SD scores for SFT showed minimal deviation (–0.3 to –0.5) compared to anthropometry (–0.7 to –1.2) and circumferences (–0.5 and –0.7), demonstrating the preservation of newborn adiposity. All the SFTs showed a moderate correlation ( r = 0.4) with the newborn weight and circumferences. There was no correlation to the anthropometry of non-obese mothers. Conclusion Term SGA newborns showed preservation of adiposity compared to AGA newborns.