Send to

Choose Destination
See comment in PubMed Commons below
Fertil Steril. 1989 May;51(5):859-62.

General and anomalous sperm disappearance characteristics found in a large vasectomy series.

Author information

Lions Gate Hospital, North Vancouver, British Columbia, Canada.


There is no accepted standard for the time after vasectomy before infertility is achieved. To help address this question, the records of 5,233 vasectomy patients who had had at least 12 ejaculations and had completed semen tests were reviewed. Seventy-five percent were able to fulfill a designated criterion for success by 4 months postoperatively, nearly 90% by 6 months, and nearly 99% by 1 year. Also found were a number of individual anomalies, including five instances of transient reappearance of sperm, four late spontaneous reversals after proof of success, and one late "delayed success" after evidence of failure. Patients can be reassured by the overall efficacy of male sterilization, but physicians also may wish to be aware of the possibility of capriciously intermittent-fitful-sperm.


The records of 5233 vasectomy patients who had had at least 12 ejaculations and had completed semen tests were reviewed to help address the issue of no accepted standard for the time after vasectomy before infertility is achieved. Patients were requested to start semen tests at 3 months postoperatively, after which monthly tests were requested until at least 2 consecutive azoospermic specimens were obtained. This constituted proof of success. If sperm had persisted for more than 6 months after vasectomy, a 3rd such test was requested. patient records provided for up to 10 tests. 4197 (80% of the study group's initial specimens, performed at a median 98 days after surgery, were azoospermic, but 188 of these (45% revealed sperm in the following specimen. At a median 137 days postoperative, 4640 (88.7%) of tests were azoospermic. Azoospermia was not regarded as synonymous with success, for which the criterion was a minimum of 2 negative and consecutive monthly samples. For the study group as a whole, there was a rapid increase with time in the proportion of successful vasectomies, with, for example, 76% of men achieving success at 137 days, 93.3% at the 215th days, and 97.2% by the 301st day. The records of the 8879 men were screened for manifestations of individual anomalous sperm persistence, disappearance, or reappearance. In 8 men, small numbers of sperm appeared intermittently over prolonged periods. These 8 individuals each had 7 or more sequential specimens reported as either "occasional sperm" or azoospermic, with the last appearances of sperm ranging from 297 to 448 days after vasectomy. 5 cases demonstrated either azoospermia or just an occasional nonmotile sperm at the initial semen test, toe be followed in 2 or 3 by substantial concentrations of sperm and then by 1 or more azoospermic tests. 4 men who had had 2 negative and consecutive semen tests, and therefore "successful" operations, were later found to have pregnant partners and significant sperm in their semen. These 4 failures followed their vasectomies by an average of 5.5 years. While for the study group as a whole, sperm disappearance rates were a function of time, the total group contained instances of considerably individual variability. The cause of these variations is unclear.

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center