Current status of the endocrinological effects of vasectomy

The relevant literature which has appeared, primarily within the last several years, in regard to the endoncrinological effects of vasectomy is reviewed. Focus is on early animal studies, examinations of interstitial tissue, short-term endocrine studies in animals and man, and long-term endocrine studies in man. Suspicion that vasectomy may influence androgen and gonadotropin status has reappeared recently because of experimental investigations of vasectomized rats and human vasectomy follow-up studies. The possibility that vasectomy is accompanied by untoward consequences to the endocrine system, which might become manifest shortly after the procedure or later in life, received support from recent animal investigations. During the 1972-1975 period, several reports appeared which attempted to clarify what effect vasectomy had upon the human pituitary-gonadal axis. Recently, there have been several prospective long-term studies on the pituitary-testicular axis in vasectomized men. Several areas where additional research is necessary are identified.     

The decision to terminate childbearing: Differences in preoperative ambivalence between tubal ligation women and vasectomy wives

Abstract

This paper examines the degree of preoperative ambivalence expressed by 255 currently married tubal ligation patients compared to 167 wives of vasectomy patients regarding the decision to terminate childbearing and aspects of the decision‐making process which account for differences between groups. Data indicate that tubal ligation women are significantly more certain and comfortable with their decision than are vasectomy wives. In order to explain this finding, analysis focused on sociodemographic factors; time factors related to the decision; variables related to communication with spouse and others; factors internal to the individual, including interest in another child and motivation for the decision; external constraints on the decision; and couple dynamics in the decision‐making process. Results indicate that group differences in ambivalence are primarily due to the effects of strong male control over the termination decision, as perceived by the wife, and a disproportionate prevalence of this pattern among vasectomy couples. An interaction effect between male dominance and group membership was also found. Implications of study results for preoperative counseling, including likely sources of future regret, are considered.     

The effects of vasectomy on testicular metabolism in the guinea-pig.

The effects of vasectomy on testicular DNA production were studied in guinea-pigs at 2 weeks and 2 and 6 months after surgery. By 6 months, vasectomy had resulted in lower testicular weight and absolute DNA, RNA and protein contents, although RNA and DNA concentrations/protein were unchanged. Incorporation of thymidine into the testis had decreased by 2 weeks after vasectomy, and continued to do so unless the ductal system subsequently ruptured and formed a granuloma when thymidine incorporation returned to normal control levels. It is suggested that in the guinea=pig vasectomy alters spermatogenesis by reducing testicular DNA synthesis.     

Compensatory payments and vasectomy acceptance in urban Sri Lanka

The effects of different levels of compensatory payment for vasectomy on sterilization acceptance were examined in 496 vasectomized men in urban Sri Lanka. The results indicate that compensatory payments significantly enhanced the participation of economically poor men in vasectomy programs, especially those who had already achieved a large family size. The proportion of poor acceptors (those with a monthly income of Rs 1000 or less) increased with higher levels of payment; the acceptor's level of education was negatively correlated with the compensation amount, and the mean age of the youngest child was higher among those who received higher payments. 60% of vasectomy acceptors reported using contraception immediately before the vasectomy, suggesting a high level of motivation not to have another child. Respondents cited high effectiveness, no extra expense, and no side effects for their wives as the main reasons for selecting vasectomy over other means of contraception, regardless of the amount of payment received. Only 5% said cash payment was an important reason for choosing vasectomy, and this response did not vary significantly by level of payment. There was no influence of payment level on postoperative complications or satisfaction. While compensatory payments significantly enhanced the participation of poor men in vasectomy programs, they were not effective in attracting poorer men with few children or those whose last child was relatively young. Overall, this study's findings suggest that the decision to provide compensatory payments and how much to provide should be based on economic and political factors, not on the grounds that higher compensatory payments have led to the recruitment of ineligible men or that the promotion of vasectomy has been at the expense of a loss in the quality of services provided.     

A review of epidemiologic studies of vasectomy

A number of epidemiologic studies of vasectomy have been published in recent years. These studies have been methodologically diverse and have involved several groups of investigators in several countries. The studies are consistent in finding no long-term effects of vasectomy on the risk of cardiovascular disease, cancer, impotence, prostatic disease, or disease related to immune function and dysfunction. Continued follow-up of vasectomized men to evaluate further the possibility of adverse effects of vasectomy is recommended. At this time, epidemiologic studies of vasectomy in man are strongly reassuring. Vasectomy decreases prostatic secretory function. In a study conducted by Sidney, no association was found between vasectomy and benign prostatic hypertrophy or prostatic cancer. Massey et al. found that the incidence of impotence was 1.9/1000 man-years of observation in men with vasectomy and 1.7/1000 man-years in non-vasectomized men, a difference that was not statistically significant. 3 studies examining the risk of malignant and nonmalignant neoplasms in vasectomized and nonvasectomized men revealed that vasectomy was not associated with an increased risk of malignant or nonmalignant neoplasms.     

Possible mechanisms of vasectomy-exacerbated atherosclerosis

Our laboratory as well as those of others have demonstrated that in experimental animals vasectomy results in immune-complex deposition not only in the reproductive tract but also in the renal glomerulus. We have shown that in two species of monkeys vasectomy results in a significant increase in atherosclerosis and have postulated that this may be due to circulating immune complexes. We have shown a mild change in arteriolar vessels in a small study of vasectomized men and have found a mild but insignificant increase in systolic blood pressure in vasectomized men over time compared to an age-matched group. One cannot ignore the fact that persistent autoimmune responses to spermatozoal antigens are generated in both vasectomized men and animals. The paucity of direct information about whether vasectomy exacerbates atherosclerosis in human subjects has made reliance on animal studies unavoidable. But to date there is no evidence that vasectomy causes a similar effect in human beings.     

Incidence of disease after vasectomy: a record linkage retrospective cohort study.

OBJECTIVE--To determine whether vasectomy is associated with an increased risk of several diseases, and in particular testicular cancer, after operation. DESIGN--Retrospective cohort study using linked medical record abstracts. SETTING--Six health districts in Oxford region. SUBJECTS--13,246 men aged 25-49 years who had undergone vasectomy between 1970 and 1986, and 22,196 comparison subjects who had been admitted during the same period for one of three specified elective operations, appendicitis, or injuries. MAIN OUTCOME MEASURES--Hospital admission and death after vasectomy or comparison event. RESULTS--The mean durations of follow up were 6.6 years for men with a vasectomy and 7.5 years for men with a comparison condition. The relative risk of cancer of the testis in the vasectomy cohort (4 cases) compared with that in the other cohorts (17 cases) was 0.46 (95% confidence interval 0.1 to 1.4), that of cancer of the prostate (1 v 5 cases) 0.44 (0.1 to 4.0), and that of myocardial infarction (97 v 226 cases) 1.00 (0.8 to 1.3). There was no evidence of an increase associated with vasectomy in the incidence of a range of other diseases. CONCLUSIONS--Vasectomy was not associated with an increased risk of testicular cancer or the other diseases studied. With respect to prostatic cancer, while we found no cause for concern, longer periods of observation on large numbers of men are required.     

Inflammatory changes in the epididymis after vasectomy in the Lewis rat

The epididymides of Lewis rats were studied at intervals up to 7 months after vasectomy, vasectomy followed 3 months later by vasovasostomy, or sham operations. Epididymal histology was related to testicular alterations and to serum antisperm antibodies as determined with an enzyme-linked immunosorbent assay. In vasectomy and vasovasostomy groups. 13 of 33 rats had testicular alterations, which consisted mainly of pronounced depletion of germ cells. Over half of the rats with testicular alterations also had severe epididymal lesions that included interstitial changes characteristic of an inflammatory response. These consisted of aggregates of mononuclear cells, including lymphocytes, plasma cells, and macrophages. The lumina of epididymides with interstitial changes contained polymorphonuclear leukocytes and/or macrophages. All animals with altered testes had greatly decreased numbers of epididymal sperm. In many instances, the lumen of the proximal cauda epididymidis was collapsed, and columnar cells of the epididymal epithelium contained many very large lysosomes. The distal cauda epididymidis was distended with sperm and debris. None of the rats that lacked testicular alterations showed epididymal changes. Mean serum antisperm antibody levels were significantly higher for rats with epididymal interstitial changes than for animals without such epididymal alterations. Infiltrations of inflammatory cells into the epididymal interstitium and lumen are part of the constellation of changes that occurs after immunization with testicular homogenates to produce experimental allergic orchitis. The observations reported here support the hypothesis that reproductive tract alterations after vasectomy in this model have an immune basis.     

Clinical, ultrasonographic and pathological features following unilateral vasectomy in rams

The effects of vasectomy on testes and related structures of animal species and men are largely disputable. These possible effects were studied in the ram, an established experimental animal model used to investigate genitalia pathophysiology. In each of five rams, vasectomy in the left spermatic cord was carried out; subsequently, the clinical and ultrasonographic features were monitored up to 12 months post-operatively. The rams were sequentially euthanatized 1, 3, 6, 9 and 12 months post-operatively; gross- and histo-pathological examination of their testes and related structures were carried out. Four of the five rams developed sperm granulomas at the proximal to the testis end of vas deferens or/and at the tail of the epididymis; these were palpable from the first and the third month after vasectomy, respectively. Ultrasonographic findings on the vasectomy side were increased size and echogenicity of the epididymal tail, as well as anechoic areas, representing sperm granulomas, visible in the epididymal tail 1 week after vasectomy and in the proximal to the testis end of vas deferens 4 weeks after vasectomy. Gross pathological findings were limited on the vasectomy side and included adhesions between the parietal and the visceral vaginal tunic, enlarged and firm epididymal tail and presence of sperm granulomas at the epididymal tail or/and at the proximal to the testis end of vas deferens; the granulomas contained creamy material. Histopathological changes were observed mainly in the epididymal tails, consisting of a central mass of spermatozoa, surrounded by a layer of macrophages, surrounded in turn by loose vascular connective tissue rich in lymphocytes and plasma cells. With the exception of signs of mild hypospermatogenesis observed in one ram euthanatized 9 months after surgery, and of a slight increase in seminiferous tubule diameter and in seminiferous epithelium height in the rams euthanatized 6 and 9 months after surgery, which are both findings of no clinical importance, no clinical, ultrasonographic, gross- or other histo-pathological changes were observed in the testicular parenchyma during a 12-month post-operative period. These results demonstrate that vasectomy has little if any detrimental effect on the morphologic characteristics of the spermatogenesis in rams.     

Semen characteristics after vasectomy in the ram

The objective of this study was to monitor the changes in semen characteristics in vasectomized rams and to determine if infertility was present 14 days after vasectomy. Experiments were performed using five cross-breed rams, aged between 18 and 30 months. Semen was collected weekly by artificial vagina from 2 months before to 5 months after vasectomy. After sexual rest for 10 days, vasectomy was performed by the cranial midscrotal approach. In all ejaculates the volume, concentration, total sperm number, motility and morphology (normal spermatozoa, loose heads) were determined and sperm viability (SYBR-14/PI) was evaluated in all semen samples collected after vasectomy. In the first ejaculate obtained 14 days post vasectomy all rams showed a significant (P < 0.05) drop in mean volume (from 1.2 to 0.5 mL), total sperm count (from 5176.8 to 51.1 x 10(6)) and morphologically normal sperm (from 84.1 to 15.7%), when compared to the last prevasectomy collection. We could also demonstrate a positive correlation (r = 0.89) between the individual cumulative total number of spermatozoa after vasectomy and the scrotal circumference measured before vasectomy. Sperm motility and viability could never be demonstrated after vasectomy and normal spermatozoa continuously decreased concomitant with an increase in loose heads. On post mortem examination 5 months after surgery, spermatocele formation and multiple sperm granulomas were present in all five rams. Our results show that in the first ejaculate collected by artificial vagina 14 days after vasectomy, no motile and viable spermatozoa could be detected. Despite weekly collections during a 5-month period after sterilization, azoospermia could never be achieved.     

The influence of vasovasostomy on antisperm antibodies in rats

Serum antisperm antibodies were studied in Sprague-Dawley rats after vasectomy and vasovasostomy. Animals received a bilateral vasectomy, a vasectomy followed 3 mo later by vasovasostomy, or sham operations. Blood samples were obtained at 1, 3, 4, and 7 mo, and antisperm antibodies were assayed by an enzyme-linked immunosorbent assay. After vasectomy reversal was performed at 3 mo, antisperm antibodies were significantly higher in rats in the vasovasostomy group at 4 mo than in animals that had a persisting vasectomy or sham operations. At 7 mo, the antisperm antibody level for the vasovasostomy group was approximately double that for the vasectomized rats. Spermatic granulomas occurred in 76% of rats after vasovasostomy. Antisperm antibody levels were higher in vasovasostomized animals with granulomas than in those lacking granulomas. The results suggest that vasovasostomy may stimulate an antibody response to sperm rather than lead to a reduced response, as was anticipated upon removal of the obstruction. Spermatic granulomas may serve as sires for continued antigenic challenge. The observed increase in antisperm antibodies after vasovasostomy in Sprague-Dawley rats may be related to their relatively low immunologic responsiveness to vasectomy, with vasovasostomy serving as a second major immunologic challenge, aided by the formation of an additional granuloma. In the more responsive Lewis strain, we previously observed a rise in antisperm antibodies after the initial vasectomy, with no further increase after vasovasostomy.     

Vasectomy reversal in Nepal

Data from 157 men in Nepal who had vasectomy reversal are analysed. Most sought reversal within 5 years of vasectomy. Half of the men sought reversal because of the death of a male child, and about one-fourth because of the loss of a female child. Re-marriage was the primary reason for only 10% of the men. Those having reversal because of the loss of a male child were generally younger, and for almost half of this group, the age of their last child at the time of their vasectomy was under 2 years. The results suggest that the demand for reversal could be considerably reduced by more careful screening of the potential vasectomy acceptors.     

Effects of vasectomy on the blood-testis barrier of the hamster.

The effects of vasectomy on the blood-testis and blood-epididymal barriers to 3H2O, [3H]inulin, and [14C]urea were examined by study of the radioactivity appearing in micropuncture samples of fluids from the seminiferous tubules and cauda epididymidis. By 4 months after vasectomy, there were changes in the blood-seminiferous tubule barrier to [3H]water and [14C]urea (increased entry) and in the blood-epididymal barrier to [3H]water and [3H]inulin (increased entry) and to [14C]urea (decreased entry). These subtle changes could have an impact on spermatogenesis and/or sperm maturation after vasectomy.     

Who has a vasectomy reversal?

A comparatively small proportion of sterilized men request vasectomy reversals, and the size of the proportion (which UK estimates place between 1% and 1.5%) depends on awareness of the availability of reversal. In this study, the characteristics of 200 cases of vasectomy reversal (the 1st 200 such operations performed in the UK) were analyzed. All 200 had been completed by 1981, the mean time from vasectomy to reversal being 4.8 years. The time figure varied according to the reason for requesting reversal, and was particularly short when the operation had been performed at the time of the partner's pregnancy. General practitioners and friends were particularly important sources of referral. 30% of the men were with the same partner and 70% a new partner. Vasectomy reversal cases tended to be younger than vasectomy patients as a whole but did not differ significantly in social class. Most requesting reversal wanted to have another child. Scattered cases requested the reversal after a partner's pregnancy termination. 12 men requested it for psychosexual reasons. In this series of reversals, spermatozoa were present in the ejaculate throughout the 20-week follow-up time in 80% of the men; the pregnancy rate was 44%. The study demonstrates the need for counselling prior to a vasectomy, especially with regard to the posibility of marital breakdown or pregnancy termination.     

Weak autoantibody reactions to antigens other than sperm after vasectomy.

Autoantibody activity against various antigens was measured by indirect immunofluorescence in 97 men about to undergo vasectomy and 170 men who had undergone the operation up to six years earlier. There was a significantly higher prevalence of weakly positive autoantibody reactions among those who had undergone vasectomy. There was, however, no evidence that vasectomy could induce stronger autoantibody reactions such as those associated with autoimmune disease.     

Risk of testicular cancer after vasectomy: cohort study of over 73,000 men.

OBJECTIVE--To confirm or refute reports that vasectomy may increase the risk of cancers of the testis and prostate. DESIGN--Computerised record linkage study of cohort of men with vasectomy and comparison of cancer rates with those in the whole Danish population; manual check of all records of patients with testicular and prostate cancer diagnosed within the first year of follow up. SETTING--Denmark 1977-89. SUBJECTS--Cohort of 73,917 men identified in hospital discharge and pathology registers as having had a vasectomy for any reason during 1977-89. MAIN OUTCOME MEASURES--Observed incidences of testicular, prostate, and other cancers up to the end of 1989. RESULTS--The overall pattern of cancer incidence in the study cohort was similar to that expected nationally. No increased incidence in testicular cancer was observed (70 cases; standardised morbidity ratio 1.01 (95% confidence interval 0.79 to 1.28)). The incidence during the first year of follow up was also close to that expected (nine cases; standardised morbidity ratio 0.80 (0.36 to 1.51)). The incidence of prostate cancer was not increased (165 cases; standardised morbidity ratio 0.98 (0.84 to 1.14)). CONCLUSIONS--The incidence of testicular cancer in men with vasectomy is no higher than in other men. Vasectomy does not cause testicular cancer and does not accelerate the growth or diagnosis of pre-existing testicular neoplasms. Data concerning a causal relation between vasectomy and prostate cancer were inconclusive.     

Consultant Surgeons and Vasectomy

In late 1971 410 consultant general surgeons and urologists—74% of a national random sample—responded to a postal survey about vasectomy. Probably about 50,000 vasectomies were performed by surgeons in England and Wales in 1970. The service was largely a private one: 60% of consultants'' hospital vasectomies were not done under the National Health Service, and, in addition, 26% of the consultants who worked in relevant specialties performed vasectomies elsewhere than in hospital (usually in private nursing homes). Based again on consultants'' estimates, probably 6,000 men in 1970 had their requests for vasectomy turned down by surgeons, or more than one turned down for every 10 done. The most common reason was that patients were “too young.”About 90% of the consultants thought vasectomy could normally be performed safely and adequately as an outpatient procedure, yet only 64% said that 90% or more of their hospital vasectomies were done on this basis. While 69% regarded services in their areas as adequate, most were in favour of more special vasectomy clinics.     

The relation between antisperm antibodies and testicular alterations after vasectomy and vasovasostomy in Lewis rats

The relationship between antisperm antibodies as determined by enzyme-linked immunosorbent assay (ELISA) and the occurrence of alterations in testicular weight and histology was studied following vasectomy in Lewis rats. The effects of vasovasostomy on antisperm antibody levels were also examined. At 1, 3, and 4 months after vasectomy, the mean absorbance values in an ELISA for sera from animals with altered testes was significantly greater than that from animals lacking testicular alterations. However, animals showing positive antisperm antibody responses were represented both in the group with testicular alterations and among those that lacked testicular damage. Levels of antisperm antibody in both vasectomy and vasovasostomy groups significantly exceeded that for sham-operated animals, but the level of antisperm antibodies in vasovasostomized animals with positive responses was similar to vasectomized animals one and four months after reanastomosis. It is suggested that persistence of antisperm antibodies or testicular alterations, or both, may play roles in limiting the restoration of fertility after vasovasostomy.