New research suggests tube tying isn't as permanent or effective as once thought

After the Supreme Court overturned Roe v. Wade, allowing states to restrict access to abortion, interest in permanent contraception options increased. For example, Google recorded the highest volume of searches for “vasectomy” in the past five years right after the Dobbs v. Jackson Women's Health Organization decision was made. A study published in April 2024 found that a rise in tubal sterilizations among females was twice as high as the increase among vasectomies in males after Dobbs. But just how permanent are these increasingly popular contraception options — especially when it comes to tubal ligation? 

A new study published in NEJM Evidence suggests that tubal sterilization isn’t always guaranteed to prevent pregnancy 100 percent. In fact, it could be less effective than some other birth control options, like the hormonal arm implant or a hormonal intrauterine device. Researchers say this could change how people view tubal ligation as a so-called “permanent” contraception option, and how providers discuss birth control options post-Dobbs.

“When we say ‘permanent,’ what it really means is that it is not reversible, you don't have the power to undo it — but it doesn't mean it may not fail,” Dr. Eleanor Bimla Schwarz, author of the study and chief of the UCSF Division of General Internal Medicine at Zuckerberg San Francisco General, told Salon. “I think what people are looking for is a method that will not fail, but we can't necessarily be promising that.” 

But tubal ligation is frequently promoted as a nearly bulletproof option that prevents pregnancy. According to the American College of Obstetricians and Gynecologists, tubal ligation is considered to be a “permanent” option, as there is less than 1 person who gets pregnant a year after the surgery. Its effectiveness in preventing pregnancy is on par with an intrauterine device and hormonal implant. This new study suggests that’s not entirely accurate. 

In the study, the authors looked at four independent rounds of the National Survey of Family Growth from 2002 to 2015. This data included self-reports from more than 31,000 women, 4,184 who underwent tubal sterilization. Within the first year after the surgery, 2.9 percent of those who had been sterilized between 2013 and 2015 became pregnant. Ten years after the surgery, the estimated percentage of those who got pregnant was 8.4 percent. 

“These data suggest that there may be nontrivial rates of pregnancy after tubal sterilization,” the researchers concluded in the study. 

Notably, the chance of pregnancy after the surgery was highest among those who were younger. There was no significant difference between people who had Medicaid-funded procedures and those whose procedures were paid by private insurance. 

As Salon previously reported, the Dobbs decision has led more women than men to seek out so-called “permanent” contraception options, emphasizing the burden women carry in a post-Roe world. Not only is the cost of tubal ligation more expensive than a vasectomy, but it is a more complex procedure. An estimated 65 percent of women between the ages of 15 and 49 use birth control, according to national statistics. Tubal ligation, which is an abdominal surgery where a person’s fallopian tubes are clamped or cut, and then removed, is used by more than 21 percent of women between the ages of 30 and 39, and 39 percent of women over the age of 40.

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“This study shows that tubal surgery cannot be considered the best way to prevent pregnancy,” Schwarz said. “People using a contraceptive arm implant or an IUD are less likely to become pregnant than those who have their tubes tied.” 

Some might be wondering how can this happen. While Schwarz prefaced her response by emphasizing she doesn’t perform these surgeries herself, it’s likely that any gap in the way that fallopian tubes were sealed can likely provide an opportunity for the sperm and egg to meet and fertilize. 

“Both eggs and sperm are very small, and all it takes is one egg and one sperm to connect,” Schwarz said. “But what we were finding is not that these were pregnancies were getting stuck in people's tubes, but really that these were pregnancies that were making it to the woman's uterus.”

In a post-Dobbs landscape, this is an important reality for women to know, Schwarz said.

“It’s scary for many people in this country right now not to have a backup of safe and legal abortion services,” Schwarz said. “Even our most highly effective methods of birth control fail sometimes, and you know, especially for women with chronic medical conditions or a reason why pregnancy would be dangerous, it can be very, very scary to learn you're pregnant when you aren't intending to be.” 

Dr. Julia Tasset, an OB-GYN and assistant professor at Oregon Health & Science University, told Salon she suspects many people reading the study will be wondering how these failures are happening. The "honest answer," she said, is that it is likely not fully understood, adding that it is possible that the true failure rate has been underestimated all along. Regardless, Tasset said she believes this is an "important new finding" that will help gynecologists better counsel patients. 

"This study underscores that even something previously felt to be as close to 100 percent as possible can still have failure rates even higher than what we anticipated," Tasset said. "And this is important new evidence that continues to clarify that picture and help give us better information that we could share with patients to make the right choices for themselves."

Schwarz said it's not a stretch to say that her research shows that an IUD or hormonal arm implant is more effective at preventing pregnancy.

“We have good data on those being very highly effective,” she said, pointing to her previous research. “We have seen that women who were using the hormonal IUD were less likely to get pregnant than those who had their tubes tied.”