The frequency of undescended testis from birth to adulthood: a review.
Level 3 - non-randomized controlled study
Systematic review of observational prevalence and cohort studies
PubMed 17488243 · doi:10.1111/j.1365-2605.2007.00770.x
What was done
The authors conducted a systematic review searching Medline, Embase, Cinahl, and the Cochrane Library to assess the frequency of undescended testis (UDT) from birth to adolescence. They included any study reporting UDT frequency and evaluated population age, number of boys examined, examination period, primary examiner, geographic area, study design, ethnicity, definitions used, and documentation of previous testicular position.
What was found
A total of 46 studies met inclusion criteria, with 23 of 46 (50%) involving newborns. Definitions of UDT were documented in half of the studies and were heterogeneous; only 11% (5/46) noted previous testicular position. At birth, UDT frequency ranged from 1.0% to 4.6% in term infants (birth weight >2.5 kg) and 1.1% to 45.3% in premature infants (birth weight <2.5 kg). In term boys, UDT frequency was 1.0–1.5% at 1 year, 0.0–2.6% at 6 years, 0.0–6.6% at 11 years, and 1.6–2.2% at 15 years.
Why it matters
This review documents the wide variation in reported cryptorchidism prevalence and indicates that the true frequency of acquired UDT remains uncertain because historical testicular position was rarely tracked.
Limits
The primary studies utilized inconsistent definitions of UDT, and only 5 of 46 studies assessed previous testicular position. Older age groups were underrepresented, and aggregate participant numbers were not stated in the abstract.
Cited by
- contradicts Approximately 20% of male infants are born with an undescended testicle.