Re: How little is enough? The evidence for post-vasectomy testing.
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Biomedical subjects
Publications and source records attributed to David C Sokal.
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BACKGROUND: Little evidence supports the use of any one vas occlusion method. Data from a number of studies now suggest that there are differences in effectiveness among different occlusion methods. The main objectives of this study were to estimate the effectiveness of vasectomy by cautery and to describe the trends in sperm counts after cautery vasectomy. Other objectives were to estimate time and number of ejaculations to success and to determine the predictive value of success at 12 weeks for final status at 24 weeks. METHODS: A prospective, non-comparative observational study was conducted between November 2001 and June 2002 at 4 centers in Brazil, Canada, the UK, and the US. Four hundred men who chose vasectomy were enrolled and followed for 6 months. Sites used their usual cautery vasectomy technique. Earlier and more frequent than normal semen analyses (2, 5, 8, 12, 16, 20, and 24 weeks after vasectomy) were performed. Planned outcomes included effectiveness (early failure based on semen analysis), trends in sperm counts, time and number of ejaculations to success, predictive value of success at 12 weeks for the outcome at 24 weeks, and safety evaluation. RESULTS: A total of 364 (91%) participants completed follow-up. The overall failure rate based on semen analysis was 0.8% (95% confidence interval 0.2, 2.3). By 12 weeks 96.4% of participants showed azoospermia or severe oligozoospermia (< 100,000 sperm/mL). The predictive value of a single severely oligozoospermia sample at 12 weeks for vasectomy success at the end of the study was 99.7%. One serious unrelated adverse event and no pregnancies were reported. CONCLUSION: Cautery is a very effective method for occluding the vas. Failure based on semen analysis is rare. In settings where semen analysis is not practical, using 12 weeks as a guideline for when men can rely on their vasectomy should lessen the risk of failure compared to using a guideline of 20 ejaculations after vasectomy.
Because of the potential importance of the lactational amenorrhea method (LAM) as a family-planning option in Egypt, we analyzed data from the 1995 Egyptian Demographic and Health Survey (EDHS) to study breastfeeding practices, use of contraception, reproductive history and sociodemographic factors for 5504 mothers with children under 3 years. According to the EDHS data, about 80% of Egyptian women breastfed for at least 6 months, and 40% breastfed for 15-18 months. Over half of breastfeeding mothers used no additional contraception. Thirty-six percent of mothers breastfeeding children younger than 6 months who reported using no additional contraception were exclusively breastfeeding and amenorrheic, but only 4% reported relying on breastfeeding for family planning. We also held eight focus group discussions with breastfeeding mothers from urban and rural Upper and Lower Egypt on their use of contraceptive methods, breastfeeding, lactational amenorrhea and LAM. Participants showed strong recognition of the contraceptive effects of breastfeeding but differed widely in their understanding of lactational infecundability and knowledge of LAM as a method. These results suggest that LAM would be widely acceptable to Egyptian women, but that an educational program about the method is needed.
We surveyed 2000 US urologists using mailed questionnaires. The aim of this survey was to estimate the incidence of pregnancy after vasectomy and to gather information on the surgical methods used. Of 586 responding urologists, 538 reported performing vasectomies, and they reported a total of 177 pregnancies during the preceding 5 years. Ninety pregnancies (51%) were attributed to unprotected intercourse during the immediate post-vasectomy period. The remaining pregnancies were attributed to recanalization or other less common causes of method failure. Based on the number of vasectomies performed by these surgeons, about 1 pregnancy was reported per 1000 vasectomies. This is probably an underestimate of the true rate. The risk of pregnancy was lower following vasectomies by surgeons who performed more than 50 procedures per year.
The purpose of this study was to identify compounds that could potentially be useful for vas irrigation at the time of vasectomy. We studied the in vitro effects of a group of membrane-active and ion-channel blocking agents on human sperm motility, viability and cervical mucus penetration. Diltiazem, an anti-arrhythmic drug, and methylene blue, an agent commonly used in vasography, showed the most promising effects with marked reduction of sperm motility and cervical mucus penetration after incubation with sperm for a short period of 15 min. Diltiazem was more effective than methylene blue in inhibiting the motility and viability of sperm. Furthermore, unlike methylene blue, diltiazem significantly compromised sperm viability. Other compounds studied, such as lidocaine, nicardipine and Neosporin((R)), showed only partial inhibitory activity. Based on the data reported herein, both diltiazem and methylene blue appear to be suitable candidates to be developed for vas irrigation at the time of vasectomy.
This nonrandomized observational clinical study evaluated the safety and acceptability of intrauterine device insertion either immediately or 2 weeks after abortion, according to the patient's preference. Participants were 300 women with first-trimester abortions who agreed to immediate or delayed insertion. End points were bleeding patterns, pregnancy, expulsion, perforation, infection and device removal at 2, 6 and 10 weeks after insertion, and acceptance rates before and after counseling procedures were improved. The overall initial acceptance rate was 35.8%, and the actual acceptance rate was 31.7%. After counseling procedures were improved, the initial and actual acceptance rates increased substantially (17.7% vs. 44.3% and 10.2% vs. 42.0%, respectively). Bleeding, expulsion rates and pain did not differ significantly between the immediate and delayed insertion groups after IUD insertion. No pregnancies, perforations or cases of pelvic inflammatory disease were recorded in either group. Immediate post-abortal insertion offers the advantage of being a painless procedure. The quality of counseling is critical to improving acceptance of post-abortion contraception.
The main purpose of this retrospective, cross-sectional study was to evaluate the effectiveness of vasectomy in an ongoing public sector program in Nepal. We evaluated semen samples from men who had previously had a vasectomy, and asked about the occurrence of pregnancies in the men's partners. In addition, the surgeons who performed the vasectomies completed a questionnaire about their techniques. A two-stage stratified sampling procedure was used to select 1263 men from among over 30,000 men, who had previously undergone a no-scalpel vasectomy, mostly by ligation and excision, in 32 districts between July 1996 and June 1999. Semen samples were preserved and analyzed at a central laboratory. A US andrology laboratory validated the lab results. Twenty-three men (2.3%, 95% confidence interval [CI] 1.1-3.6) had >/=500,000 sperm/mL in their semen. Fifteen of those men reported pregnancies conceived after their vasectomy. In addition, six men with azoospermia reported pregnancies for which conception occurred within 3 months after vasectomy. Eleven men with azoospermia reported pregnancies for which conception occurred more than 3 months after vasectomy. Reported pregnancy was more likely in younger partners. The life table pregnancy rates for all men interviewed were 0.7 (95% CI 0.2-1.1), 1.7 (95% CI 1.4-2.1) and 4.2% (95% CI 3.2-5.2) at 3, 12 and 36 months, respectively. In low-resource, programmatic settings, vasectomy failure rates may be higher than commonly cited rates, especially in younger populations. Additional research is needed to determine if other occlusion techniques could reduce failure rates. Counseling on vasectomy should always convey the possibility of failure and partner pregnancy.
Family Health International (FHI) and EngenderHealth conducted a multicenter, randomized controlled trial to evaluate a fascial interposition (FI) component of a vas occlusion procedure for male sterilization. A data monitoring committee (DMC) was established to provide independent review of the interim report. The DMC met to review the interim report after enrollment of 552 men. As planned, an estimate of the hazard ratio (HR) for successful vasectomy for the FI group versus the no-FI group controlling for age of the participant and level of experience of the surgeon was obtained for the interim report using Cox's proportional hazards regression. The main analysis comparing time to vasectomy success, defined as two consecutive azoospermic semen samples, was highly significant and met the prespecified level for stopping enrollment (HR=1.54, p<0.01). However, a troublesome age by vasectomy technique interaction became apparent in the analysis. FI was clearly beneficial for younger males. However, the trend for older men was not as clear. The DMC recommended continuing the trial to better study this interaction and obtain more data to clarify the effect of FI for older men. After consulting further with the DMC, the study statisticians presented the interim report to senior management at FHI. A meeting between FHI senior management and the DMC followed. After much deliberation, trial enrollment was terminated. Follow-up of participants already enrolled in the study continued as planned. This paper presents the issues involved in the decision to terminate the study.
Vasectomy is a commonly used, highly effective method for the control of fertility in the human male. It is almost always performed as an outpatient procedure, is safer than tubal occlusion and has few side effects. The number of people relying on vasectomy as a method of contraception varies widely from country to country. Though vasectomy is highly effective, failures may occur due to re-canalization of the vas, surgical error, anatomical variants or failure of contraception during the post-operative waiting period. One of the disadvantages of this technique is that sperm are present in the posterior end of the vas following surgery and hence patients have to use alternative methods of contraception for a waiting period of 12 weeks to 15 weeks before relying on a vasectomy for contraception. This review summarizes recent research on vasectomy conducted by Family Health International, USA.