What is believed to be a permanent birth control solution may actually be less effective at preventing pregnancy than less invasive methods, new research suggests.
University of California researchers found as many as five percent of women who underwent a tubal ligation, commonly known as getting a person’s tubes tied, later became pregnant.
Tubal ligation is meant to be irreversible and is the most common form of contraception used worldwide – with more women choosing it than oral contraceptives.
Most women who undergo the procedure, which involves cutting the fallopian tubes so eggs cannot travel to be fertilized by sperm, do so because they are already mothers and do not want to have more children, while many younger women choose to remain childless.
Previous estimates for pregnancies among women getting their tubes tied have hovered around one percent, but a new study found post-ligation pregnancies ‘may be considerably more common than many expect’ – between three and five percent.
Tubal ligation, also known as getting one’s tubes tied, was found to be less effective at preventing pregnancy than common, reversible contraception measures such as IUDs
The researchers concluded that for women, particularly younger women, a reversible form of contraception such as an intrauterine device (IUD) or an arm implant could be more effective than the so-called ‘permanent’ option.
The study, led by UC San Francisco researchers, collected medical data from more than 31,000 women aged 15 to 44 who participated in the National Survey of Family Growth from 2002 to 2015.
Of that total, 4,184 reported having undergone the procedure, in which doctors clamp down the fallopian tubes or cut and remove them.
Across four waves of data collection in that period, between 2.9 and 5.2 percent of women became pregnant despite undergoing the procedure.
In the most recent wave of data, from 2013 to 2015, nearly three percent of women had become pregnant within the first year of having the surgery. Almost nine percent of them became pregnant within 10 years of having the procedure.
Dr Eleanor Bimla Schwarz, an internal medicine physician at UCSF and author of the study, said: ‘For people who have chosen a “permanent” method, learning they got pregnant can be very distressing. It turns out this is, unfortunately, a fairly common experience.
‘This study shows that tubal surgery cannot be considered the best way to prevent pregnancy.
‘People using a contraceptive arm implant or an IUD are less likely to become pregnant than those who have their tubes tied.’
An IUD releases hormones that prevent pregnancy over 99 percent of the time and can remain in place for up to five years.
An implantable birth control that is inserted in a person’s upper arm is also more than 99 percent effective and can stay in the arm for three years.
The team of researchers called for more research into the effectiveness of the procedure that around 700,000 women opt to undergo every year.
This is more than those who choose to take birth control pills – believing they are making a permanent family planning decision.
Around 18 percent of women choose to get their tubes tied, according to CDC data, while 14 percent of women take birth control pills. About 10 percent of women choose long-acting contraception, including an IUD or an arm implant.
With 700,000 women opting for tubal ligations in a single year, 20,000 of them could later become pregnant, based on the study’s findings.
The UCSF findings were published in the New England Journal of Medicine Evidence.
Researchers added that in the wake of the Supreme Court’s decision to overturn the federal right to an abortion in the Dobbs v Jackson case and the domino effect of states enacting bans that followed, being informed about the best contraception options is paramount.
Dr Schwarz said: ‘Since the Dobbs’ decision, many more people are worried about how pregnancy may impact their health and family life.
‘This is especially true for patients with medical conditions like diabetes and high blood pressure that can complicate pregnancy.’
Public interest in surgical sterilization surged after the Dobbs decision was issued three years ago, primarily among 18- to 30-year-olds.
According to a 2024 report from public health researchers in Pittsburgh and Boston, the monthly rate of tubal ligations rose from 2.84 procedures per 100,000 women per month pre-Dobbs to 58.02 procedures per month for women after the decision was issued.
Dr Schwarz added: ‘For people who have chosen a “permanent” method, learning they got pregnant can be very distressing. It turns out this is, unfortunately, a fairly common experience.’
