Establishment of a normal range of penile length in preterm infants

Recognition of micropenis is important because it may be the only obvious manifestation of pituitary or hypothalamic hormone deficiencies. Alternatively it may indicate the presence of dysgenetic testicular tissue with malignant potential. Previously published normal ranges for premature males are based on small sample sizes, with few infants <30 weeks and none <28 weeks.

Intensive and Special Care Nurseries, Royal Women's Hospital, Melbourne, Victoria.

188 consecutive male infants, inborn and outborn, with gestational age <37 completed weeks were examined in the first week of life. They included multiple births (n=51) and small for gestational age infants (n=16). Infants with hypospadias (n=3) or an endocrine disorder (n=1) were excluded from the study. MANOEUVRE: Stretched penile length was determined by a single examiner (RT) using a standardized measure.

A mean penile length with associated 95% confidence intervals is described for infants between 24 and 36 weeks inclusive. The relationship between penile length (PL, cm) and gestational age (GA, weeks) was: PL=2.27+0.16 GA.

This study confirms the normal range for penile length of premature male infants 30-36 weeks and defines the normal range <30 weeks. This should prove useful to paediatricians, paediatric surgeons and endocrinologists dealing with the increasing number of surviving male infants <30 weeks in whom penile size is questioned.