Human male infertility caused by degeneration and death of sperm in the epididymis.

Four patients with persistent oligospermia and necrospermia were found to have severely degenerated sperm in the ejaculate. However, in those examined, testicular sperm were ultrastructurally normal, indicating that sperm degeneration and death was occurring during epididymal passage or storage or both or upon mixing with the seminal plasma at ejaculation. Seminal plasma was found to be nontoxic to normal donor sperm. In three patients, frequent ejaculation (two ejaculates per day for 4 or 5 days) was used to deplete epididymal sperm reserves and reduce the period spent in the epididymis. This resulted in a threefold to sevenfold increase in percentage of motile sperm in the ejaculate and a similar increase in sperm motility index. The authors propose the term "epididymal necrospermia" to describe this previously undefined type of male infertility.