Penile size in healthy Nigerian newborns: country‐based reference values and international comparisons

AIM: To establish normal reference values for penile size in Nigerian newborn boys and to compare those values with standards from other populations. METHODS: A total number of 261 healthy newborn boys delivered at gestational ages of 28 weeks or more were enrolled in the study. Penile lengths and widths were measured within 72 h of birth. RESULTS: The mean (±SD) penile length in the 261 Nigerian males studied was 3.4 ± 0.48 cm, while the mean mid-shaft diameter was 1.2 ± 0.14 cm. Compared with data from other populations, Nigerian newborn boys had similar penile sizes to those reported for US Caucasian boys (mean 3.4 cm), but significantly greater penile sizes than those reported for boys from China and Hong Kong (mean 3.0 and 3.1 cm, respectively; both p < 0.001). There was a slight, but significant, difference in size between Nigerian and Malaysian boys, with Malaysian boys having greater penile sizes (mean 3.5 cm; p < 0.05). CONCLUSION: A Nigerian newborn with a penile length of <2.39 cm can be considered to have a micropenis.