Calf circumference as a predictor of low birth weight babies.

To identify an inexpensive, reliable predictor of low birth weight capable of being utilized by untrained personnel, anthropometric measures were performed on 1600 newborns in Kanpur, India. This analysis indicated that, for a birth weight of 2500 g, the critical limit of calf circumference was 10.8 cm or less. Critical limits for crown-heel length, head circumference, chest circumference, midarm circumference, and thigh circumference were equal to or less than 45.2 cm, 32.2 cm, 30.1 cm, 9.0 cm, and 15.4 cm. All these measurements were significantly correlated with birth weight. This correlation was highest for calf circumference (r = 0.98), thigh circumference (r = 0.93), and chest circumference (r = 0.86). The highest sensitivity of detecting low-birth-weight infants was found for calf circumference (98.4%), followed by thigh circumference (91.6%) and head circumference (76.7%); specificity was 98.2% for thigh circumference and 90.0% for calf circumference. Traditional birth attendants can be trained easily to screen out high-risk newborns by measuring calf circumference.