Thousands of women who undergo ‘permanent’ contraceptive surgery still get pregnant years later, study finds

New research suggests that what is seen as a permanent method of contraception may actually be less effective at preventing pregnancy than less invasive methods.

Researchers at the University of California found that as many as five percent of women who underwent tubal ligation (tying of the fallopian tubes) later became pregnant.

Tubal ligation is an irreversible method and is the most widely used form of contraception worldwide. Women choose this method more often than oral contraception.

Most women who undergo this procedure, in which the fallopian tubes are cut so that the eggs cannot be fertilized by sperm, do so because they are already mothers and do not want any more children. However, many younger women choose to remain childless.

Previous estimates of the pregnancy rate among women who had their tubes tied hovered around one percent, but a new study has found that pregnancies after tubal ligation “may be significantly more common than many expect” – between three and five percent.

The researchers concluded that for women, particularly younger women, a reversible form of contraception, such as an IUD or an arm implant, may be more effective than the so-called “permanent” option.

The study, led by researchers at UC San Francisco, collected medical data from more than 31,000 women ages 15 to 44 who participated in the National Survey of Family Growth from 2002 to 2015.

Of these, 4,184 reported having undergone the procedure, in which doctors clamp or cut and remove the fallopian tubes.

In the four waves of data collection over that period, between 2.9 and 5.2 percent of women became pregnant despite having undergone 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 after surgery, and nearly nine percent of them became pregnant within 10 years of the procedure.

Dr. Eleanor Bimla Schwarz, an internist at UCSF and author of the study, said: ‘For people who have chosen a ‘permanent’ method, learning that they are pregnant can be very stressful. It turns out to be a fairly common experience, unfortunately.

‘This study shows that tubal surgery is not the best way to prevent pregnancy.

‘People who wear a contraceptive implant in the arm or an IUD are less likely to become pregnant than people who have had their fallopian tubes tied.’

An IUD releases hormones that prevent pregnancy in 99 percent of cases and can remain in place for up to five years.

An implantable contraceptive device placed in a person’s upper arm is also more than 99 percent effective and can remain in the arm for three years.

The research team is calling for more research into the effectiveness of the procedure, which is undergone by some 700,000 women each year.

This is more than the number of people who choose to take the contraceptive pill, believing that they are making a permanent decision about family planning.

According to the WHO, about 18 percent of women choose to have their fallopian tubes tied. to CDC datawhile 14 percent of women take the contraceptive pill. About 10 percent of women choose long-acting contraception, including an IUD or an arm implant.

The study findings show that 700,000 women opt for tubal ligation in one year. Of these, 20,000 can later become pregnant.

The UCSF findings were published in the New England Journal of Medicine Evidence.

Researchers added that given the Supreme Court’s decision to strike down federal abortion rights in Dobbs v. Jackson and the domino effect of states enacting bans in the wake of the decision, it is imperative to be informed about the best contraceptive options.

Dr Schwarz said: ‘Since the Dobbs ruling, many more people are concerned about the impact of pregnancy on their health and family life.

‘This is especially true for patients with medical conditions such as diabetes and high blood pressure, which can complicate pregnancy.’

Public interest in surgical sterilization increased after the Dobbs ruling three years ago, especially 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 before Dobbs up to 58.02 procedures per month for women after the decision was made.

Dr Schwarz added: ‘For people who have chosen a ‘permanent’ method, it can be very stressful to hear that they are pregnant. It turns out to be a fairly common experience, unfortunately.’