Most of us have heard stories about people getting pregnant after undergoing a tubal ligation or vasectomy. How often does this happen? Should you worry about a pregnancy after choosing a permanent method of birth control?
In the vast majority of cases, the answer is no, you shouldn’t worry. However, it is possible. Statistically speaking, vasectomies are said to fail about .25 percent of the time. This isn’t a large number of births, but this adds up to about 1 in 4000 births, according to Harvard Medical School.
The cause of vasectomy failure is a process called recanalization. This happens when the cut ends of the vas deferens grow back together. This can happen just after the procedure or much later. If recanalization happens soon after the vasectomy, it is more likely to be caught in the semen analysis done after the procedure. If it happens later, it is usually not caught until a pregnancy occurs.
Sterilization failure in women happens more frequently than with men. Tubal ligation fails about 1.45 percent of the time. A study in California showed that 145 women in 10,000 got pregnant after a tubal. Again, this is a small number of births in the overall picture.
Failure often occurs in a similar way as in men. The ends of the tubes can grow back together, as in vasectomy failure. If the tubes are very close or touching, but not grown back, an egg can get through. This is quite rare, but does exist as a remote possibility.
The way the procedure is done can affect the chances of getting pregnant after a tubal ligation. If the tubes are cauterized during the procedure, there is less chance of the tubes growing back together or an egg getting through the end of one tube and into the other. The amount of the tube that is removed can decrease the chance of failure as well. Removing a portion of the tube reduces the chance that they will grow together.
The overall success rate of sterilization procedures is very good. While there are no guarantees, in most cases the procedure works and pregnancy will not occur. It is actually more common for couples to change their plans and seek out surgery to reverse the procedure. For this reason, pregnancy after sterilization is not a big worry.