Penile length of term newborn infants in multiracial Malaysia

Ting TH, Wu LL
Correspondence: Dr Ting Tzer Hwu, thting@media.upm.edu.my

ABSTRACT
Introduction Micropenis may be an important sign of underlying hypogonadism or pituitary hypofunction in the neonatal period. Penile lengths of normal newborns have been reported in many Western populations. However, the data may not be applicable in the Asian or the multiracial Malaysian population. Our study aimed to establish the normal penile length and testicular volume in term newborn infants in the major ethnic groups in Malaysia.
Methods The stretched penile length and testicular volume were measured in 340 normal term newborn infants (195 Malays, 129 Chinese and 16 Indians).
Results The mean penile length in Malay term newborn infants was 35 +/- 4 mm, which was similar to Chinese infants. The mean testicular volume was 2.5 +/- 0.6 ml in Malay and 2.4 +/- 0.5 ml in Chinese infants. There was no significant difference between the groups. The sample size for the Indian group during the study period was inadequate.
Conclusion Using -2.5 standard deviations as the cut-off for micropenis, a Malay or Chinese newborn infant in Malaysia with a penile length of less than 25 mm is considered to have a micropenis and further evaluation is warranted.

Keywords: micropenis, penile length, term newborn, race, testes volume
Singapore Med J 2009; 50(8): 817-821