Reference values for penile and clitoral lengths of healthy term Egyptian newborn infants

Examination of the external genital organs is an integral part of the routine physical examination of the newborn. Early recognition of micropenis or clitoromegaly is important as they may be the only obvious manifestation of pituitary or hypothalamic hormonal deficiencies at birth. Studies suggest that differences in penile or clitoral anthropometry may exist between different populations. Therefore, reference values for genital organs dimensions should be available and well known to medical personnel. We aim to establish reference values for the penile length in Egyptian newborn boys and reference values for the clitoral length in Egyptian newborn girls and to define micropenis and clitoromegaly according to Egyptian reference values.

A total of 500 healthy term newborn boys and 500 healthy term newborn girls were enrolled in the study. Stretched penile length and clitoral length were measured during the first 7 days of postnatal life. Birth weight, length and head circumference were measured and recorded.

The mean (±SD) stretched penile length was 3.16 ± 0.41 cm. The mean (±SD) clitoral length was 0.51 ± 0.13. There was no significant correlation between penile or clitoral length, and body weight, length or head circumference.

Our study provides reference values for normal penile length and clitoral length in Egyptian newborns. Our study suggests that among healthy term Egyptian newborns, penile length of less than 2.13 cm may be considered micropenis and clitoral length of more than 0.83 cm may be considered clitoromegaly.