Search for reversing a vasectomy and you find success rates above 90 percent. That figure is usually accurate, it just measures something other than what you want to know. It counts sperm returning to your semen, not a child.
Those two numbers sit far apart, and the gap grows with the years.
In the largest study of reversals, sperm returned in 86 percent of men while 52 percent of couples conceived. Below is the full breakdown, plus the study that contradicts the interval story.
Can a vasectomy be reversed?
Sometimes, with microsurgery, and you should not count on it. The operation is called a vasovasostomy: a microsurgeon stitches the two ends of the vas deferens back together under a microscope. Thuisarts.nl, the patient site of the Dutch College of General Practitioners (NHG), is brief about it.
Reversal is difficult, often fails, and men usually stay less fertile afterwards.
That is exactly why a vasectomy is presented as permanent in every counselling conversation. It is not contraception with a pause button.
So do not treat the possibility of a repair operation as a safety net for your original decision. If that net feels necessary, that says something about the decision.
What is the difference between patency and pregnancy?
Patency means sperm cells are back in your semen. Pregnancy means a child arrives. Clinics almost always advertise the first number, because it is higher and because it can be measured in the man alone.
The second number is the only one a couple cares about.
In the Vasovasostomy Study Group research, which analysed 1,469 microsurgical reversals, sperm returned in 865 of 1,012 men examined, so 86 percent. Of the 810 couples whose outcome was known, 52 percent conceived (PMID 1997700).
That is a 34 percentage point gap within the same group of men.
So always ask a clinic which of the two numbers they are quoting. It is one sentence, and it shifts your expectation considerably.
What are the odds after 5, 10 or 15 years?
Both chances fall over time, and the pregnancy rate falls faster. This is the most important table in the whole topic, and it appears on almost no Dutch page. The figures come from that same study of 1,469 reversals.
Find the row that matches your own number of years.
| Years since the vasectomy | Sperm returned (patency) | Pregnancy |
|---|---|---|
| Less than 3 years | 97 percent | 76 percent |
| 3 to 8 years | 88 percent | 53 percent |
| 9 to 14 years | 79 percent | 44 percent |
| 15 years or longer | 71 percent | 30 percent |
Watch how the two columns diverge. The left falls from 97 to 71, the right from 76 to 30.
Say you were sterilised at 34 and you are considering a reversal at 45. You land in the 9 to 14 year row. Sperm returns in about 79 percent of men, and about 44 percent of couples conceive.
That is not a poor figure. It is simply something very different from the 90-plus you read on a clinic page.
Does that interval story always hold?
Not according to every study, and you rarely hear that. A German cohort from 2010 found no relationship at all between the length of the blockage and the chance of patency or pregnancy. What did predict outcomes in that study was the age of the female partner (PMID 19906186).
Two good datasets pointing different ways, that is the honest state of things.
I think you should know that, even though it makes the story messier. Anyone showing only the tidy table is selling more certainty than exists.
Practically it changes your thinking on one point. If your partner's age weighs in, a reversal is never a decision about your body alone.
The passing years then count twice. That is an uncomfortable sentence, and I think it is a true one.
Can a vasectomy also undo itself?
Very occasionally, and that is different from a repair operation. The vas deferens can in rare cases grow back together, which is called recanalisation. Andros quotes a chance of 1 to 3 per 1,000, and in an audit of 105,393 procedures 0.04 percent were late failures.
That is roughly 1 in 2,500 (PMID 38989696).
A late failure is exactly that: a man with an earlier clear semen check who turns out to have sperm again later. Rare, but not zero.
So it is not a route back to fertility you can plan around. It is a residual risk on the contraception, nothing more.
Which tests belong with a reversal decision?
A semen analysis after the operation, and sometimes hormone values around the wider fertility question. The semen analysis shows whether sperm has returned and what it looks like. It is done by the clinic, and we perform no vasectomies, no reversals and no semen analyses.
Be clear about where blood testing stops here.
No blood value predicts whether a reversal will succeed. What hormones can show is whether production in the testicle is running. FSH, LH, inhibin B and testosterone together give context on that.
Some men map that side alongside the clinic's process, for instance with the IVF partner screening or the Hormones Man panel. Always discuss an abnormal result with your GP.
How to read a semen analysis is covered in semen analysis values. The broader list of causes when conception does not happen is in male infertility causes and in trying to conceive.
The full story on the procedure itself starts at vasectomy: how it works, and the long-term considerations are in long-term disadvantages.
What do you do with these numbers?
Use them in two directions. If you are facing the original choice, read the table as a reason to treat the procedure as permanent. If you are weighing a reversal now, use it to ask exactly which number a clinic is promising you.
That is a fair question, and a good clinic simply answers it.
What I would not read into it is a reason to rule out a reversal. A 44 percent chance of pregnancy is a real option for many couples, and the cost and the weight of the operation belong in that same balance.
What it is not is a guarantee. Nobody can give you one, and anyone who does should be distrusted.
Calling a clinic soon? Ask one question up front: is the percentage you quote the patency rate or the pregnancy rate. The answer tells you immediately how honest the rest of the conversation will be.
Sources
- Belker AM, et al. Results of 1,469 microsurgical vasectomy reversals by the Vasovasostomy Study Group. Journal of Urology. 1991. PMID 1997700.
- Magheli A, et al. Impact of obstructive interval and sperm granuloma on patency and pregnancy after vasectomy reversal. International Journal of Andrology. 2010. PMID 19906186.
- Peacock J, et al. Complications of vasectomy: results from a prospective audit of 105 393 procedures. BJU International. 2024. PMID 38989696.
- Thuisarts (NHG). Sterilisatie bij man. thuisarts.nl
Every blood test result at Caliber includes a professional assessment from a BIG-registered doctor. For treatment decisions, always discuss your results with your GP.
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