Estimations of total serum testosterone levels in Nigerian term neonates at birth using anogenital distance measurements.

Abstract

Background In genital anomalies, measurement of total testosterone is required but is expensive and technically difficult to assay. Therefore, the measurement of anogenital distance, which is non-invasive and cheap, could be used to estimate total serum testosterone in neonates. The objective if this study is to determine the relationship between total serum testosterone and anogenital distance and estimate total serum testosterone levels in term neonates using measurements of anogenital distance. Methods This was a prospective cross-sectional study. Consecutive healthy term neonates were recruited in the first 72 h of postnatal life. Anogenital distance was measured with a digital vernier calliper. Total serum testosterone was determined using enzyme linked immunoassay. Results A total of 240 term neonates comprising 124 (51.7%) males and 116 (48.3%) females were studied. The overall mean anogenital distance was 19.7 (7.7) mm and 26.5 (3.7) mm for males which was more than twice 12.4 (2.3) mm for females (t = 35.3, p < 0.001, 95% confidence interval [CI], 13-14). The overall mean total serum testosterone level was 267.1 (204.8) ng/dL; and 357.4 (241.7) ng/dL in males which was more than twice of 170.6 (80.7) ng/dL for females (t = 7.9, p < 0.001, 95% CI, 144-221). There was positive correlation between total serum testosterone and anogenital distance (r = 0.425, p < 0.001). The correlation was stronger in males than in females. The linear regression equation was as follows: total serum testosterone (ng/dL) = 44.3 + 11.3*AGD (mm) with 95% CI, 8-14. Conclusions The known value of anogenital distance could be used to estimate total serum testosterone levels in term neonates.