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Contraception UPDATE

Risk of Pregnancy After Vasectomy

Lee Warner, PhD, MPH; Denise Jamieson, MD, MPH; Ajay Nangia, MBBS, FACS

A new Cochrane analysis provides insight into the no-scalpel technique as the preferred method for vasectomies.

Vasectomy, or male sterilization, is an option for couples seeking a permanent method of contraception. Although ObGyns generally do not perform vasectomies, they may be called upon to provide counseling and answer questions for patients and their partners who may be considering this procedure and weighing its risks and benefits with other contraceptive options. Therefore, practicing ObGyns should be familiar with vasectomy, including the effectiveness of the procedure.

Vasectomy is a minor outpatient surgical procedure in which the vasa deferentia are separated, ligated, or occluded to prevent sperm from passing into the ejaculated seminal fluid. The procedure is generally performed under local anesthesia in 20 to 30 minutes, is considered among the safest and most effective forms of contraception, and represents the most effective method available for males. Vasectomy is also among the most widely used methods of contraception in the United States; more than 500,000 procedures are performed each year.1 Calculations from the most recent national data indicate that an estimated 9% of women of reproductive age in the United States (approximately 3.5 million couples) rely on vasectomy for contraception.2 The use of vasectomy is highest among currently married couples and increases with age, education, and parity.

Various surgical techniques are typically used for vasectomy. One recent US survey of vasectomy providers reported that procedures involving a combination of ligation and cautery were the preferred methods.1 No-scalpel techniques that use a sharp-pointed, forceps-like instru ment to puncture the scrotum have increased markedly in popularity and now account for nearly half of all reported vasectomies. The no-scalpel technique also requires less time for the operation than traditional techniques and may result in a faster return to sexual activity.3

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Rates of Pregnancy

Although vasectomy is considered one of the most highly effective contraceptive methods, pregnancy can occur. The overall risk of pregnancy after vasectomy is generally believed to be <1% and tends to vary by the experience of the surgeon and technique used, although data are limited.4 Most studies define vasectomy failure by evaluating whether sperm were present in the ejaculate.5,6 However, few studies have assessed pregnancy as an outcome.5,7-11

One study that did assess pregnancy risk subsequent to vasectomy was a secondary analysis from the US Collaborative Review of Sterilization (CREST), a prospective, multicenter cohort study of sterilization among women of reproductive age. In this study, 6 pregnancies were reported during telephone interviews with 540 women whose husbands underwent vasectomy.7 The cumulative probability of failure from CREST was estimated to be 7.4 per 1,000 procedures 1 year after vasectomy and 11.3 per 1,000 procedures at years 2, 3, and 5.

Most pregnancies occur during the first 3 months of the post-vasectomy period. These pregnancies are largely attributed to the failure of sexually active men to use effective backup contraception until follow-up semen analyses have been conducted to confirm the absence of sperm. Although such failures are suspected to be user-related, they also may result from technical failure, early recanalization, or other causes; the source of these failures cannot easily be distinguished from available data.4,5 Late failures after negative initial semen analyses also have been reported and may account for nearly half of pregnancies following vasectomy.7,8 Recent evidence suggests that such failures are most frequently caused by spontaneous recanalization of the vas; these vasectomies occasionally need to be repeated. 8,12,13

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Limitations of Current Data

The low pregnancy rates reported for vasectomy should be considered in light of the considerable methodologic limitations inherent in previous studies.1,4,7,8,14 Most of the few studies conducted have been secondary analyses of studies not designed to examine the contraceptive failure rates associated with vasectomy, or studies that used less rigorous research designs, including retrospective reviews of case series or cross-sectional evaluations.

Studies have been further limited by inadequate descriptions of the duration of and procedures used to ascertain follow-up, high rates of dropout, lack of data on long-term effectiveness, reliance on self-report of the woman versus clinical confirmation of pregnancies, and lack of paternity testing to confirm that resulting pregnancies belonged to the vasectomized men. An additional concern is that most studies were conducted several years ago and likely do not reflect failure rates associated with currently practiced procedures. Very few studies have rigorously examined rates of pregnancy after vasectomy for different occlusion methods in clinical trials, making comparisons difficult across different techniques.1,4,15 Thus, although failure rates are believed to be extremely low, rigorous prospective cohort studies and randomized trials are still needed to document the short-term and, particularly, long-term risks of pregnancy following vasectomy.

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Protocols for Follow-up and Counseling Recommendations

The effectiveness of vasectomy is typically measured as having at least 1, and preferably 2, consecutive azoospermic semen analysis conducted after approximately 3 months or 20 ejaculates following the procedure, whichever comes first. A recent systematic review of studies suggested that 1 post-vasectomy semen analysis documenting azoospermia after 3 months and 20 ejaculations may be sufficient.6 Further, 1 recent study found that setting an appointment for follow-up improved the likelihood that vasectomized men would return a specimen for semen analysis.16 Protocols for follow-up of vasectomized men vary widely across providers, and there are no official recommendations on how best to measure vasectomy effectiveness, although such guidance is pending from the American Urological Association. Most protocols are based on the time elapsed since vasectomy rather than the number of post-vasectomy ejaculations, although there is no clear consensus for implementation of either guidance in practice.1 Regardless, effective backup contraception should be used until sperm are no longer detectable as confirmed by semen analysis. This practice is particularly important given that a substantial minority of vasectomized men will still have sperm in their ejaculate at the initial semen analysis at 3 months.17 Compliance with this recommendation is suspected to be poor, underscoring the importance of counseling patients that vasectomy is not effective immediately.1

Clinicians are also advised to inform patients who are considering vasectomy, particularly those younger in age or involved in unstable marriages, that the procedure should be considered permanent. Studies indicate that a small proportion of patients or their partners express regret post-vasectomy,18 with men younger than 30 being the most likely to request vasectomy reversal.19 Therefore, the decision to undergo the procedure should be weighed carefully. Although pregnancy has been successfully achieved after vasectomy reversal, the procedure is expensive and complex, and the likelihood of success depends on the number of years since the vasectomy, as well as the female partner’s age. Patient counseling also should include communication about the potential health risks of vasectomy. The most common immediate complications are localized pain, temporary bruising, bleeding into the scrotal area, and infection. Long-term risks include the possibility of post-vasectomy pain syndrome, a chronic pain syndrome that occurs in a small minority (3% to 5%) of men. There is no evidence that the risk of prostate cancer is elevated after vasectomy.4,20,21 Similarly, available evidence from studies suggests no increased risk of testicular or other cancers, cardiovascular disease, or other health problems associated with vasectomy.22

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Summary

In summary, vasectomy provides a safe, effective option for couples looking for permanent contraception. However, other long-acting, highly effective contraceptive methods that are reversible (eg, contraceptive patch or implant, progestin IUD) and gaining in popularity may be appropriate options for many couples. ObGyns should be comfortable providing counseling on these methods, as well as a broad range of contraception options, for their patients.

Disclaimer: The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

The authors report no actual or potential conflict of interest in relation to this article.

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Lee Warner, PhD, MPH, is Associate Director for Science, with the Division of Reproductive Health, Centers for Disease Control and Prevention (CDC), Atlanta, GA. Denise Jamieson, MD, MPH, is a medical officer in the US Public Health Service and Chief of the Unintended Pregnancy, STD, and HIV Intervention Research Team, Women’s Health and Fertility Branch, CDC. Ajay Nangia, MBBS, FACS, is Associate Professor, Department of Urology, University of Kansas Medical Center, Kansas City, KS. If you have questions about this article, contact Dr Nangia at www.urologyatkumed.com/faculty_nangia.asp.

References

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18. Jamieson DJ, Kaufman SC, Costello C, Hillis SD, Marchbanks PA, Peterson HB; US Collaborative Review of Sterilization Working Group. A comparison of women’s regret following vasectomy versus tubal sterilization. Obstet Gynecol. 2002;99(6):1073-1079.
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