Maldescent of the testes--an epidemiological study.

The case histories of 2,362 newborn boys were evaluated for congenital testicular maldescent. These data, obtained from the prospective follow-up study "Pregnancy and Child Development" sponsored by the Deutsche Forschungsgemeinschaft, are discussed in the light of new findings on morphological changes in this disorder. The aetiology of maldescent of testes is considered to be heterogenous and could not be clarified by investigating 26 factors which might be regarded as possible causes of the abnormality. The difficulties in achieving a correct classification of the various forms of maldescended testes are emphasized and are demonstrated by data from this collaborative study. Considering the frequency of non-descent at the ages of 9 months (3.3%), 18 months (2.9%), and 36 months (2.5%), we believe we have found some evidence for spontaneous descent in a proportion of cases during the first 3 years of life. If this is confirmed by proposed new studies, the findings will have to be weighed against the recommendations of the 1974 International Health Foundation that therapy should be performed during the 2nd year of life or earlier.