Dear Dr. G,

My name is BK and I am 26 years old.

I recently came across your column and really hope you can help me.

I am a healthy woman who has a healthy sexual relationship with my boyfriend.

Although not actively trying for a baby, I am currently not on any contraception, and we have unprotected intercourse.

My period has been late for nearly three months, and I initially thought this was due to me using some antifungal medications. I think I am pregnant!

To cut a long story short, I told my boyfriend I am expecting his baby. I was shocked to find out he has already had a vasectomy two years prior to our relationship, and he was led to believe vasectomies is a form of sterilization and completely fail-proof.

Needless to say, my boyfriend is adamant it is impossible for him to impregnate me, and this has created a huge strain on our relationship!

I am so sorry to put Dr. G on the spot, can you tell me is it totally impossible for my boyfriend to get me pregnant after he has had a vasectomy?

Is vasectomy really fail-proof? If not, what is the failure rate of vasectomy, and why do vasectomies fail?

Surely, there is an interval when live sperms are still in the system to cause pregnancy? If so, what is the interval?

I am very stressed with the current situation and really hope Dr. G can help.



Vasectomy is a surgical intervention performed with the intention of permanent contraception. During this procedure, the vas deferens on both testicles are segmentally cut and tied to prevent the flow of sperms mixing with the seminal fluid. This will result in “normal” ejaculation, without the alteration of the climatic sensation, amount, colour, odours or even taste of the semen (so I was told), despite having no active sperms within the ejaculates.

As such this mode of sterilization is easily performed and has virtually no long-term impact on the sexual pleasure of men. The acceptance of such contraception is gaining popularity amongst men who will not have more children. In North America and European countries, vasectomy surgeries are at around 10% with some countries reaching 20%. Even in conservative Asian countries like South Korea, the vasectomy rate is reported to be as high as 21% as a form of permanent contraception. Worldwide, New Zealand has the highest levels of vasectomy, as 18% of all sexually active men and this constitute 25% of all married men!

With so many men putting their trust in vasectomy as a mode to enjoy the pleasure of unprotected sex with no pregnancy consequences, it is reasonable to ask the question on the efficacy of vasectomy to completely occlude the passage of the stubborn little fellas! Despite the near perfect efficacy, vasectomy is still not 100% “play and no pay” foolproof. Yes, that’s right, a guy can have the snip and still get the partner pregnant! And it is not the “milkman” that is responsible!

Before sending chills down the spines of millions of men who have had the vasectomy and worry about its failure rate, let me reiterate the fact that vasectomy failure is exceedingly rare!

Vasectomy failure can be classified into early and late failure. Early failure is by far the most common, when the pregnancies occur due to unprotected sex too soon after the snip. “Hangers-on” Sperms usually can survive in the vas deferens months after the surgery. Most clinicians would recommend a post-procedural semen analysis to verify a successful outcome. Many men may have failed to do so due to inconvenience, forgetfulness or embarrassment. Of course, some men may be such an “eager beaver” and start having non-protective intercourse and end up with failures. In fact, FDA has even cleared a home test kit called SpermCheck vasectomy that allows men to perform the test themselves; sadly the compliance for the post-vasectomy semen analysis still remains low.

Late failure of vasectomy is rare, but documented in the medical literature. The Royal College of Obstetricians and Gynecologists states vasectomy failure rates in the late stages to be about one in 2000 vasectomies. One review in 2005 revealed the total failure rates of 183 from 43,642 vasectomies (0.4%). Sixty pregnancies were also reported after a review of 92,184 vasectomies, which translates to a total failure rate of 0.07%.

In the darkest hours of the World War II, Winston Churchill famously said: “Success is not final, failure is not fatal: It is the courage to continue that counts!” When Dr. G is often put on the spot to verify whether the unlikely event of pregnancy is possible after the snip, his advice for those facing the Darkest Hours is: “Success of vasectomy is almost final, failure may seem fatal: It is the courage to do a semen analysis now that counts to verify the failure!”

On that note, good luck!

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