Gestational Age-specific Centile Charts for Anthropometry at Birth for South Indian Infants.

Objective: To construct centile charts for birth weight, length and head circumference for infants born from 24 to 42 weeks of gestation and to compare with the other national and international growth charts. Study design: Observational descriptive study. Subjects: All consecutively live born singleton infants from 24 to 42 weeks of gestation. Methods: Data were retrieved for the birth weight, length and head circumference of infants born from July 1999 to October 2009. Smoothened percentile curves were created separately for the male and female infants by Lambda Mu Sigma (LMS) method. The new curves were compared with the other Indian and international growth charts. Results: Raw and smoothened curves for weight, length and head circumference centiles at birth were created from 31,391 (males: 16,054 and females: 15,337), 28,812, (males: 14,730 and females: 14,082), and 28,790 (males: 14,724 and females: 14,066) infants, respectively. Females infants were lighter than the male infants, especially from 35 weeks onwards. On comparing the study curves with the other Indian growth curves, for infants less than 35 weeks, the mean birth weight for the study infants were similar or lower and for infants greater than 35 weeks, they were higher. On comparison of our weight centiles with the international data, across all gestations and across all centiles, our birth weights are lower. Conclusion: The updated centile charts in this study may be used as reference charts for the birth weight, length and head circumference for the local population. Using earlier growth charts or the Western charts would misclassify the infants at birth into SGA or LGA.