Normative data on penile and anogenital measurements of term male infants in Sagamu, Nigeria.

Aim: To document normative data on penile size and anogenital distances of apparently normal term male infants in Sagamu, Nigeria.

Methods: This cross-sectional study was carried out on 303 term male infants within the first 72 hours of life. Stretched penile length, penile width and three measures of anogenital distances were recorded: anogenital distance-1, anogenital distance-2 and anoscrotal distance.

Results: The mean (±SD) stretched penile length and penile width were 39.4 ± 4.2 mm and 11.0 ± 1.0 mm, respectively. The mean values for anogenital distance-1, anogenital distance-2 and the anoscrotal distance were 48.7 ± 3.9 mm, 42.8 ± 4.6 mm and 25.5 ± 3.9 mm, respectively. Only penile width and anogenital distance-1 significantly correlated with all the anthropometric parameters but anogenital distance-1 had the strongest correlation (p < 0.01 for all).

Conclusion: The observed mean stretched penile length was greater than previously reported. Local references are preferable in interpreting anogenital measurements in newborns to avoid diagnostic errors. There is need for a consensus on the definition of micropenis.