Pregnancy after a vasectomy: Is it possible?

Vasectomy is one of the most effective forms of birth control available, but conceiving a child after a vasectomy is possible. There are three primary ways unintended pregnancy can occur after a vasectomy:

  • Having sex without contraception before the man’s sperm count is confirmed to be zero
  • Natural reversal, also known as recanalization
  • Surgical error

Sperm still present in semen (non-zero sperm count)

After a vasectomy, live sperm may still be present in a man’s semen for a number of months. This means that there is still a risk of impregnating a woman after the operation. Alternate contraception must be used until there is no sperm present (azoospermia).

Most doctors advise their patients that they should be sterile after two to three months and/or 20-25 ejaculations, but these are simply guidelines. It is still possible for a man to get a woman pregnant even if he is outside of these ranges. This is why doctors generally instruct their patients to have at least one semen analysis performed by a lab at some point after their operation. A sperm count is the only way to be certain a man is sterile.

Suggested reading

When a pregnancy occurs after vasectomy due to unprotected intercourse before the “all clear” is given, it is known as a “technical error”. While most men understand that they can still get a woman pregnant immediately following their vasectomy, a surprisingly large portion of men (40% to 50%) don’t go back for a semen analysis.1

Recanalization (spontaneous natural reversal)

A recanalization occurs when sperm are able to escape from the cut end of the vas deferens due to microscopic channels that have formed in the patient’s scar tissue. These tiny channels may be the result of a sperm granuloma or other complications. If these microchannels develop and the two severed ends of the vas deferens are very close or touching, sperm may be able to travel from one section of the tube to the other.

Recanalization, which occurs early on, will be discovered as part of the post-vasectomy semen analysis and occurs in less than 1% of vasectomies. However, it is possible (but unlikely) for recanalization to occur after the man has been given the “all clear.” Late recanalization is extremely rare and occurs in approximately 1 out of 2000-3000 vasectomies.2

Suggested reading

Surgical error

Although uncommon, it is possible for a vasectomy to fail due to a surgical error. This is why it’s important to find a skilled doctor who has a good track record and has performed numerous operations. General physicians will often offer vasectomy services, but it’s usually best to go with a urologist due to their higher levels of experience and specialization.

The risk of surgical error (however small it may be) is another reason why the post-vasectomy semen analysis is so crucial.

Chances of becoming pregnant after vasectomy

The vast majority of post-vasectomy pregnancies occur in the first few months after the operation when the man may still have active sperm in his ejaculate and the couple doesn’t use an alternate form of birth control. As mentioned previously, these are known as “technical failures” and are not the result of an unsuccessful operation.

Even taking into account these early failures due to “user error” the efficacy of vasectomy is still favorable to many forms of birth control. The early failure rate of vasectomy is in the range of 0.3–9% and the late failure rate is in the range of 0.04–0.08%.3 If birth control is used until the man is cleared by semen analysis, the risk of unwanted pregnancy after a vasectomy will go further down.

These figures will vary depending on the source and the parameters of the study, but the general consensus is that when a man follows his doctor’s post-operative instructions carefully and waits for the all-clear before having unprotected sex, the chances of conceiving after vasectomy are very low.


Chances of unintended pregnancy after a vasectomy are extremely low. But it’s important to keep in mind that:

  • There no way to be 100% certain a man is sterile (unable to conceive) until semen analysis has shown he has a zero sperm count.
  • You must use alternate forms of contraception until laboratory tests confirm sperm is not present in the man’s semen.
References and futher reading has a strict sourcing policy. We rely on evidence-based medicine, peer-reviewed studies, reputable clinical journals, and medical associations. Learn more about how we ensure our content is accurate and up-to-date by reading our editorial policy.
  1. Bradshaw A, Ballon-Landa E, Owusu R, Hsieh T-C. Poor Compliance With Postvasectomy Semen Testing: Analysis of Factors and Barriers. Urology. February 2020:146-151. doi:10.1016/j.urology.2019.10.026
  2. Labrecque M, Hays M, Chen-Mok M, Barone MA, Sokal D. Frequency and patterns of early recanalization after vasectomy. BMC Urol. September 2006. doi:10.1186/1471-2490-6-25
  3. Zini A, Grantmyre J, Chan P. CUA guideline: Vasectomy. Can Urol Assoc J. 2016;10(7-8):E274-E278. doi:10.5489/cuaj.4017
Read the comments (27)

Medically reviewed by

Dr. Leann Poston, MD

Review date

May 13, 2021

Authored by content team

Last updated

July 15, 2020

Comments (27)

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  1. So my husband had a vasectomy 20 years ago. I am now over a week late and scared to death that I am pregnant. Is it possible for it to reverse itself after 20 years???

  2. Hello, I have a 3-year-old, my husband had gotten a vasectomy almost 2 years ago he did not go back to the doctor to see if his soldiers were still good. So does anyone know if I can still get pregnant? I have been trying but nothing yet.

  3. Good day, my husband had a vasectomy about 7 years ago. He went for semen analysis 12 weeks after vasectomy was done, and we were told it was safe to have unprotected sex. 7 years after the vasectomy, a lady claims that my husband made her pregnant after they had sex a few times. My husband and I went again for semen analysis to make sure he is still clear of semen, and the test shows no trace of swimmers.

    Is this possible to make the other lady pregnant? While the latest semen analysis shows no trace of semen?

  4. I’m 25. My husband is 50 and had a vasectomy 18 years ago. I just learned we are having a baby in August, and last year he found out about two 17-year-olds he had. I’m wondering if the hospital would legally have to reimburse the cost of the vasectomy?

  5. Hi, I am really looking for an answer. My husband had a vasectomy. I think, in September 2016, and we married in 2017. I want a kid. I talked about it to him, but I can feel he doesn’t want a child because one day, when we were talking about having kids, he told me to go find another man, so I feel hurt. Sometimes he talks about adoption, but I want my own.

    I am only 26 years old, with no kids. He is older than me. I am really stressed out and wondering what I should do. I don’t want to cheat on my husband. I would be really disappointed I couldn’t have my own child.

  6. Hi, I just turned 36, my partner is 43. Reading these comments hasn’t filled me with hope. My partner had a vasectomy in September 2017. He has had a retest 15th January 2018 and discovered that his counts are still there but at low levels. I have my monthly cycle symptoms at the moment, the same ones I had years ago. I was waiting to come on, and I was actually pregnant. I’m absolutely pooping my pants. We did it because we already have 6 children between us—his been ages 22,19 and 12. Mine 15 and 3, we just want to make memories now. Not new babies.

  7. My partner never went back to be checked after his vasectomy. It’s highly unlikely since, I’d say it’s been 15 years, but I’m three weeks late.

    • I’m in the same boat. My husband had his vasectomy 13 years ago. I’m 2 weeks late and left wondering… what if??? My husband says it’s highly unlikely. So… did you find out if you’re pregnant or not?

  8. Hello, I don’t know if anyone will answer, but what are the chances I could get pregnant from my boyfriend? He had his vasectomy over 15 years ago. I’m just curious.

  9. My husband’s vasectomy reversed itself after 15 years. Our daughter is such a blessing. He was back on the operating table before she was even born.

    • My husband had his vasectomy 16 years ago while he was with his first wife. We have been married for 12. Every day I pray that his vasectomy repairs itself. You’re very lucky to have your daughter.

  10. I plan to have a vasectomy reversal after 22 years of being successful with having no kids. I am divorced and plan to marry a younger woman. She is 27 years younger than me. I’d like to have a child from her. Is there a possibility of having a child once the reversal is done?


  11. This was for the response about releasing semen. The man can still ejaculate after having the procedure. There just isn’t supposed to be any “soldiers” swimming in it.

  12. Okay, my husband had a vasectomy done four years ago. He refuses to give me a specimen of his semen after the procedure. What are the chances I’m going to get pregnant from him?

    Percentage wise… I’m guessing it’s like 0.15%, right? His philosophy (and mine too) is they had to mess up something! Okay, give me the ratio? 1 in 500,000 women gets pregnant after their partner doesn’t follow-up with the doctor…

  13. I need some answers. Nearer to the start of our relationship, my boyfriend told me he had a vasectomy. He already has children from a previous relationship. We haven’t used protection as there has been no need to. Recently when we have had sex, he has released semen, which has never happened before. I asked a family member who was top of the class in science, and he said there is a chance that the strings could have either grown back or clipped themselves back together. I don’t know if this is true or not, which is why I need some real answers. Is there a chance that his vasectomy could have reversed itself?

  14. My husband had a vasectomy almost 14 to 15 years ago. I went to the doctors because I experienced slight bleeding, my doctor did an ultrasound and found out today 6/4/2010 that I have a sac in my uterus getting a pregnancy test done to confirm tomorrow. Wish me luck.

    • Did you think that was your period? How was the bleeding? The color? My husband had a vasectomy 3 years ago. I want another one, but he doesn’t want to do a reversal. He did not go back after he had it done to check if his sperm was still good. So we’ve been doing it with no protection, and right now, I started bleeding a little light red, but it’s not my period. How long did it take you to get pregnant?

  15. Well, I am a mom to be for the 3rd time. I was dating a man for almost a year and a half – off and on, he told me he had a vasectomy and so there is no way I can get pregnant. Not true.

    I dismissed my late period and other symptoms due to stress. I was not with anyone else at the time, and when I took a test, I was convinced in my head that it would say no – I was STUNNED! I started to cry because I knew that he would never believe me. I told him the news, and that was our last conversation. I asked him to get tested. He refused, saying I was crazy, …etc. This breaks my heart because I was SO careful, and I did not plan another child at this time in my life, and I will raise it alone.

    Please, no matter how it turns out – keep in mind the feelings of that child. Sometimes the right thing to do is the hardest. You will know in your gut – what that is for you. I wish you all the best.

  16. Not sure if you’re even still checking this, but it seems how the last response was October 08′ decided to reply. Probably won’t be as comforting considering it’s coming from the wife and not the husband of our situation, but my husband and I have been together for 1.5 years now.

    September 08′ I hadn’t had my monthly. Still, I decided it was stress because there was no way I was pregnant since my husband had a vasectomy done 12 years ago after his 2nd child with his ex-wife, but as a couple of weeks went by I went out and bought a pregnancy test to put my husband at ease. And well, let’s just say as of today, January 27, 2009, I’m currently one day from being 20 weeks pregnant and honestly still in shock that this happened. I haven’t cheated or been unfaithful to my man, think if you’re going to cheat you might as well end the relationship because obviously, it’s not working. But we haven’t had a sperm check done to see if he’s still supposedly sterile, so who knows, maybe the vasectomy reversed itself, either way, I look at this as a miracle because, as you said in your post what are the chances of this happening. Anyways hope your situation ended on a good note.

  17. Hi, On July 9th of 2008, my husband had a vasectomy. In early September, semen analysis was done and came back clear with no sperm. Last week (October 21st), I found out that I’m pregnant! The pregnancy was dated to only three weeks old, so conception occurred after sterility was confirmed. I haven’t had sex with anyone else besides my husband. You’d think that getting pregnant with “no sperm” be impossible, but somehow it happened to us. A couple of days ago, additional semen analysis was done, and it still came back azoospermic (no sperm present). Not sure how “semen analysis” is performed, but they don’t seem to be very accurate.

  18. Hi, To the man who has had a vasectomy 12 years ago and his wife is pregnant. Paternity testing will only break your heart if the child isn’t yours! I live in a similar position, but I don’t want to know if the child is mine or not because the birth was so beautiful and the baby girl opened her eyes wrapped up in a nappy, and these lovely blue eyes looked up at me!

    My Doctor said there is a beautiful little baby (and she was) who needs my help, and I will always be her Daddy, and this has proved the cause regardless of getting a paternity test! (My Ex now) said she didn’t know but had had an affair, so I don’t want to know because my daughter lives with me know and is 14 years old. Go with what your heart tells you. Miracles can and do happen for a reason,

    Hope this helps,


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