Indian Pediatrics 2001; 38: 934-935  

Calf Circumference for Identifica-tion of Low Birth Weight Babies

The study by Samal and Swain(1) from eastern India suggests that calf circumfer-ence measurement is a good method for screening low birth weight babies in the community. We would like to share the results of a similar study done in northern India enrolling 254 full term, normal single-ton babies. The birth weight was recorded to the nearest 50 g and other measurements like calf circumference (CC), mid-arm circum-ference (MAC), mid-thigh circumference (MTC), crown-heel length (CHL), head circumference (HC) and chest circumference (CHC) were also recorded by standard techniques within 24 hours of birth.

The results showed a low birth weight prevalence of 18.5% which is lower than usual because no preterms were included in the study. The highest correlation was observed with chest circumference (0.753) followed closely by calf circumference (0.734) and head circumference (0.712). Further analysis showed significant ‘t-values’ for calf, head and chest circumfer-ences. Linear regression keeping birth weight as a dependent variable did not show much variation after deleting MTC, CHL and MAC, R2 being 0.6651 and 0.6601 before and after deletion of these three variables. Thus, MTC, CHL and MAC did not contribute much to the predictive value of the model and were deleted from further analysis. The derived cut-off values for various indicators, sensitivity and specificity, negative and positive predictive values are shown in Table I.

Table I - Performance of various proxy indicators for identification of low birth weight 

The present study gives a cut-off value of 8.5 cm as compared to 10.0 cm for the published study(1), as well as previous studies(2,3). However, all these studies have not mentioned the mean values for birth weight and various surrogates. The differ-ences can be explained on the basis of geographical, racial and socio-economic status and nutrition of the mothers, which highly influence the capacity of the fetus to grow. The predictive power increased once CC was combined with HC or CHC. Since CC and HC are readily accessible for measurement even during winters, they can be easily evaluated without disturbing the environment of a warm neonate.

We conclude that calf circumference correlates best with the birth weight <2500 g, yet the cut-off values may vary for different geographical areas and racial distributions.

Verinderjit S. Virdi,
B.K. Jain,
Harmesh Singh,
Department of Pediatrics,
Government Medical College and 
Hospital, Ludhiana, Punjab, India.

References

1. Samal GC, Swain AK. Calf circumference as an alternative to birth weight for identifica-tion of low birth weight babies. Indian Pediatr 2001; 38: 275-277.

2. Neela J, Raman L, Balakrishna N, Rao KV. Usefulness of calf circumference as a measure for screening low birth weight infants. Indian Pediatr 1991; 28: 881-884.

3. Raman L, Neela J, Balakrishna N. Com-parative evaluation of calf, thigh and arm circumference in detecting low birth weight infants–Part II. Indian Pediatr 1992; 29: 481-484.