Before a vasectomy procedure is done, urologists often have consultation sessions with the patient to go through the procedure, effectiveness, risks, and possible complications.

During these consultations, the doctor will also highlight other birth control options just to make sure that a vasectomy is exactly what the patient wants.

One of the most repeated questions during this period is ‘what are the chances of the vasectomy failing?’ Here’s all you need to know!

How common are vasectomy failures?

Vasectomies are highly effective and failures are uncommon. In the first 3 to 6 months after the procedure, the chances or failure are at their highest, between 0.3% and 0.9%.

Late-stage failures are rarer with a vasectomy failure rate of less than 0.01%.1

The no-scalpel vasectomy is non-invasive and poses fewer risks of complications and ultimately the chances of failure.

Top causes of vasectomy failure

During a no-scalpel vasectomy, the doctor punctures a small hole in the scrotum and pulls out the vas deferens. The tube is cut, both ends are tied back together and then put back in, after which the doctor seals the wound.

It is a simple outpatient procedure that takes around 2 hours but as with any other surgical procedure, there are risks of failure.

Here are the main reasons why your vasectomy could fail.

Reconnection of the vas deferens tubes

There are instances where the cut tubes rejoin and allow sperm to pass through.

In most cases, the scar tissue that forms after the procedure creates small channels in which sperm can be transported from one end of the tube to the other, reversing the vasectomy. This process is referred to as recanalization.

Recanalization mostly happens within the first three months of the vasectomy and late recanalization, while rare, is hard to detect until pregnancy occurs.

Risks of the tubes rejoining are higher if an open-ended vasectomy is done or sperm tissue remains in the surgical site.

Surgical error

Sometimes the doctor may miss the vas deferens or fail to seal the tubes correctly. When this happens, sperm can still be transported from the testes to the penis and may result in pregnancy.

The good news is that surgical errors are easily detectable during the post-vasectomy checkups.

Your doctor may recommend having the procedure repeated to correct the error.

Having sex too soon

The effectiveness of a vasectomy is not immediate. You have to wait for at least 12 weeks until the doctor confirms that your sperm no longer contains semen.

It takes around 90 days for the semen to be completely sperm free so it’s recommended that you use other forms of birth control until you are cleared.

How to Reduce Vasectomy Failure Rate

Vasectomy failures are very rare.

The best thing to do would be to hold off unprotected sex until your semen sample comes back clean.

You should also have an experienced surgeon perform the procedure as this will reduce chances of failure and complications

Links to sources used

  1. CUA guideline: Vasectomy – NCBI –