Stretched penile length and total serum testosterone in term male neonates

Abstract

Introduction: the reference values of stretched penile length vary with different ethnic group. There is paucity of data on the reference range of total serum testosterone in neonates especially in Africa. This study therefore was to determine the normal stretched penile length, total serum testosterone levels in term male newborns and to correlate them with anthropometric parameters.

Methods: this was a prospective cross-sectional study. One hundred and twenty-four consecutive healthy term male neonates were recruited in the first 72 hours of postnatal life. The stretched penile length (SPL) was measured with a rigid metric ruler. Weight, length and occipitofrontal circumference were also measured. Total serum testosterone level was determined using Enzyme Linked Immunoassay. Data were analysed using the Statistical Package for Social Sciences for Windows version 20.

Results: a total of 124 term male neonates were recruited. The postnatal age of recruited neonates was one to 70 hours with a mean of 22.8 ± 17.6 hours and the mean of estimated gestation age was 38.5 ± 1.3 weeks. The range of stretched penile length was from 2.1 to 3.9 cm with a mean of 3.2 ± 0.4 cm and SPL less than 2.2 cm was considered as micropenis. The mean total serum testosterone level was 357.4 ± 241.7 ng/dl. The SPL had a positive correlation with the birth weight, length and total serum testosterone. The total serum testosterone and birth length were predictors of stretched penile length.

Conclusion: among the studied population the mean stretched penile length was 3.2 cm and mean total serum testosterone was 357.4 ng/dL.