Endocrine Abstracts (2010) 24 P15

Clitoral and penile sizes in healthy newborn babies in Ibadan, Nigeria

O O Jarrett1, O O Ayoola3 & M Ritzen2


1University College Hospital, Ibadan, Oyo State, Nigeria; 2Karolinska Institutet, Stockholm, Sweden; 3Royal Manchester Childrens Hospital, Manchester, UK.


Background: Standards of penile and clitoral lengths are useful for diagnosis of genital abnormalities. Micropenis could be the only sign in pituitary/hypothalamic dysfunction while clitoromegaly may reflect abnormalities of neonatal and maternal origin. Ambiguous genitalia if missed at birth could be fatal especially in cases of congenital adrenal hyperplasia. There are no African reports on normal reference ranges of both penile and clitoral sizes. This study aimed to generate key information that did not exist on the size of external genitalia of newborn babies in Nigeria.

Objective: To establish the normal reference values for penile and clitoral sizes in Nigerian infants and to compare with standards from other ethnic populations.

Methods: A total number of 515 healthy newborn babies delivered at gestational ages 28 weeks or more were enrolled in the study. Clitoral or penile lengths and widths were taken less than 72 h after birth in all of them.

Results: The mean penile length in the 264 Nigerian males studied was 3.4±0.49 cm while the mean width was 1.2±0.17 cm. Nigerian newborn had similar penile sizes as the Caucasians (3.4±0.3 cm); larger than the Chinese (3.1±0.4 cm) but significantly smaller than those of Indian (3.6±0.4 cm), Turkish and Malaysian origin. The mean clitoral length in the 251 Nigerian females studied was 7.5±1.8 mm while the mean clitoral width was 4.4±0.89 mm. The clitoral sizes were significantly larger than those in the Caucasian (4±1.24 mm), Korean and Japanese babies.

Conclusion: The overall figures in Nigerian newborns deferred from values obtained from other countries. There were significant variations in clitoral and penile sizes between different ethnic populations. The measurement of genital sizes should be part of routine newborn physical examination.

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