An implant used to sterilize women poses a serious safety concern, according to a new study published in the British Medical Journal.

Findings showed women who had Essure permanent birth control fitted had a 10-times greater risk of needing a repeat operation than women who had conventional sterilizations.

Regulators say the device is safe but are monitoring the situation following complaints from users about Essure problems and side effects such as pain and misplacement. Bayer says Essure’s safety and efficacy are backed up by evidence.

The study comes less than a month after a U.S. Food and Drug Administration (FDA) advisory panel met to discuss questions about the safety and effectiveness of Essure permanent birth control. The FDA is considering whether to take action such as toughening warning labels.

The research published in the October 2015 issue of British Medical Journal tracked 8,000 women through coding data on medical records from outpatient ambulatory surgical centers in New York state between 2005 and 2013 who had the Essure device implanted and 44,000 women who underwent conventional tubal sterilization to compare how well the procedures worked.

According to the findings, one year after receiving an implant, 2.4% of Essure patients required follow-up surgery. Only 0.2% of women who underwent minimally invasive laparoscopic sterilization required an additional procedure.

When all is said and done, the 2.4% number means that women who undergo sterilization with Essure coils are 10 times as likely to need repeat operations a year later than those who have traditional tubal ligation/sterilization surgery.

Still, Bayer pointed out that because all women who have the Essure device receive a routine check-up three months after having the device fitted, this may partly explain why more in the study had follow-up surgery.

Essure Problems

Approved in 2001, Essure has implantable coils that are inserted into the fallopian tubes vaginally, without incisions or general anesthesia. Three months later, patients get an X-ray with dye to confirm that scarring has successfully blocked the tubes.  About 750,000 women use Essure permanent birth control worldwide, and 70% of them are in the U.S.

The FDA has received more than 5,000 reports of “adverse events,” while a Facebook group called Essure Problems has 23,000 members who say the device caused debilitating pain or allergic reactions to nickel in the coils, or both.

In 2014, the FDA said it would investigate the product. Bayer then released data from a 5-year follow-up study showing that Essure caused pelvic pain in only seven percent of participants. But some experts in the field struck back, saying that only some participants in the original study were followed for the full five years and that some women still experience serious Essure problems.

Back in September, the FDA convened an independent panel of experts to discuss Essure’s risks and benefits and to see whether it should face heightened scrutiny. The panel urged the agency to review additional studies examining the device’s safety, and chastised regulators for approving the product without a gold-standard, randomized clinical trial. While the FDA is not bound by its panel’s advice, it generally follows its recommendations.

If you or a loved one opted to have Essure coils implanted for purposes of permanent, non-hormonal female sterilization and suffered adverse side effects, you may be entitled to compensatory damages.