DETERMINATION OF NORMATIVE VALUES OF STRETCHED PENILE LENGTH AND TESTICULAR VOLUME OF APPARENTLY HEALTHY TERM IGBO NEONATES IN ENUGU

Abstract

Establishing the normal penile length of newborn males for every population is of paramount
importance as various studies have shown disparity in penile length among different racial and
ethnic groups. The reference value currently in use was derived from the Caucasoid race and
may not be applicable to Afro population. In addition, the extent of in –utero development of
penile length depends partly on the level of testosterone secreted by the testes, which has been
found to have a direct positive correlation with testicular volume. There is also a linear
relationship between stretched penile length and gestational age, especially from mid trimester
until birth.
Indigenous data on the normal penile length and testicular volume of healthy Igbo neonates will
help in early diagnosis and prompt treatment of anomalies of penile length and testicular volume
such as micropenis and testicular agenesis.
This descriptive, cross-sectional and hospital based study was undertaken to determine the
normative values of stretched penile length and testicular volume of apparently healthy term
Igbo neonates in Enugu. Eight hundred and eleven apparently healthy term male neonates within
the first three days of life were studied. The stretched penile length was measured using
Schonfeld method while the testicular volume was determined with the Prader orchidometer.
The mean and standard deviation of both stretched penile length and testicular volume were
calculated. In addition, the stretched penile length and testicular volume for each gestational age
(37 to 42 weeks) were determined. The relationships between penile length and testicular volume
with growth parameters were determined using the Pearson’s correlation coefficient while the
linear relationship between the variables were established using the linear regression analyses.
The mean stretched penile length was 3.46cm ± 0.44cm and the mean testicular volume was
1.74mls±0.62. There was a significant positive correlation between the stretched penile length
and testicular volume(r =0.592, p =0.0001) as well as body length(r= 0.357, p = 0.0001) and
birth weight(r = 0.224, p=0.0001) There was a significant linear relationship between stretched
penile length and testicular volume(R =0.356,p=0.0001) as well as body length
(R2=0.117,p=0.0001) using linear regression analysis. Formula was derived for predicting
stretched penile length using testicular volume.
The first set of standards for stretched penile length and testicular volume according to
gestational age in healthy term Igbo neonates has been established and the mean stretched penile
length was found to differ from those reported among other races. These determined values can
be used as reference values for Igbo and Nigerian babies at large.

DETERMINATION OF NORMATIVE VALUES OF STRETCHED PENILE LENGTH AND TESTICULAR VOLUME OF APPARENTLY HEALTHY TERM IGBO NEONATES IN ENUGU