Measurement mid arm circumference and study its correlation with the birth weight of the babies

Abstract

Background: To know the correlation between birth weight and mid arm circumference (MAC). To test the sensitivity and specificity of cut off limits of MAC for the identification of low-birth-weight babies <2000 gm and <2500 gm.Methods: In this observational study, 300 children were enrolled. Birth weight was measured using electronic weighing scale of accuracy 10 grams within 24 hours of life. Right MAC was measured using non-stretchable tap to the nearest of 0.1 cm at the midpoint between tip of olecranon process of ulna and the acromian process of scapula. Data was analyzed using SPSS. Different cut offs for MAC and their sensitivity, specificity to identify LBW babies <2.5 kg was analyzed through ROC. The study was approved by the institutional ethics committee.Results: MAC highly correlated with weight (p<0.001). A MAC of <10 cm, predicts a birth weight of ≤2500 gm, with a sensitivity of 93% and specificity of 49% MAC of ≤9 cm, predicts a birth weight of ≤2000 gm, with a sensitivity of 95% and specificity of 87%. Regression values were analyzed and formula for detecting birth weight for the given MAC was derived.Conclusions: A positive correlation existed between midarm circumference and birth weight (p<0.001). A cut off value of 10 cm of MAC for identification of low-birth-weight babies weighting ≤2500 gm and 9 cm of MAC for identification of low-birth-weight babies ≤2000 gm with optimum sensitivity and specificity.