Bayer said the Essure device is 99 percent effective when inserted properly and when women use birth control until a follow-up visit several months after the procedure. (Courtesy of Bayer/Courtesy of Bayer)

Kim Hughes never had heard of Essure when she decided in late 2009 that her child-bearing days were behind her. Her doctor told her about the small sterilization device, saying that implanting it in her Fallopian tubes would be simple, safe and virtually painless.

At first, that seemed true. But over time, the 38-year-old woman from Bowie, Md., said, she developed constant pelvic pain, stomach swelling, dizziness, irregular menstrual cycles and fatigue. She visited various doctors but got few explanations. Only when she discovered a Facebook support group with accounts from women complaining of similar struggles did she begin to suspect Essure.

“I didn’t have these problems before,” said Hughes, who earlier this year underwent a hysterectomy on a doctor’s advice. “It completely changed my life.”

On Thursday, the Food and Drug Administration will hold a public hearing to consider the stories of women like Hughes, who claim they have been seriously harmed by the permanent birth-control device. The agency called the meeting earlier this year amid mounting reports of complications linked to the device — more than 5,000 at last count — and a long-running social media campaign by women who want Essure pulled from the market.

Bayer HealthCare Pharmaceuticals is also facing several lawsuits over Essure, which it acquired in 2013.

The company says that the product, initially approved by the FDA in 2002, has a long history of safety and effectiveness. Officials acknowledge that some women have experienced problems, such as cramping, bleeding, nausea or fainting. But they say those complications occur only in a small fraction of patients — a fact, they say, that has been lost amid a relentless campaign on Facebook and Twitter.

“Clearly, the data for Essure shows the benefits outweigh the risks,” said Edio Zampaglione, vice president of medical affairs for women’s health at Bayer. “There’s nothing [we’ve seen] with the product itself that says we’ve got a defective product or something that needs to be taken off the market.”

So far, the FDA has agreed. The agency said it has examined patient reports, data from two studies conducted after Essure’s initial approval and other academic research about the device.

“To date, we have found no conclusive evidence in the literature indicating any new or more widespread complications definitely associated with Essure,” the agency says on its Web site, although officials continue monitoring “to make certain that its benefits of providing women with a non-incisional sterilization choice continue to outweigh its risks.”

Yet several times in recent years, the FDA has required updates to the product’s labeling to include a warning to women who might have a sensitivity to nickel and to add more information about risks such as chronic pain and pregnancies that have occurred even after the device was implanted. The FDA also has met with patients and advocacy groups.

Despite the controversy surrounding it, Essure itself is little more than a small, flexible coil made in part from an alloy of nickel and titanium. A doctor inserts the coil into each Fallopian tube, in a procedure that typically takes less than 15 minutes. Over roughly three months, tissue is supposed to form around the inserts, blocking the tubes and preventing pregnancy.

Bayer said the device is 99 percent effective when inserted properly and when women use birth control until a follow-up visit several months after the procedure. The company estimates that about 750,000 women have used Essure globally. About a million of the devices have been sold worldwide, the vast majority of them in the United States.

The disagreement over Essure’s safety and effectiveness extends beyond patients to doctors who have used it.

“I’ve probably done well over 1,000 patients by now,” said Peter Rothschild, a gynecologist in Northern Virginia. “I don’t doubt that there are individuals out there who have had problems. But in my own practice, in my own personal experience, I have just not had patients with serious problems.”

Rothschild, who has received payment from Bayer to teach the implantation procedure to other doctors across the country, said his wife opted for the device years ago. He said Essure carries some serious risks, such as perforating the uterus or Fallopian tubes if it is implanted improperly. But he said laparoscopic tubal ligation, more commonly known as having one’s tubes tied, is a more invasive procedure that also risks damaging internal organs and requires a patient to be put under anesthesia.

“If the only option on the market is laparoscopic tubal ligation, I think that would be a shame,” Rothschild said, adding that both approaches are safe in most cases. “I think women deserve to have this option.”

Mitchell Creinin thought the same thing when he began using Essure with patients years ago. “I was very enamored with it,” said Creinin, professor of obstetrics and gynecology for the University of California at Davis Health System in Sacramento.

But over time, as patients returned with problems, he became disillusioned with the device. Creinin and colleagues reexamined the results from clinical studies cited in Essure’s approval and concluded that it was not nearly as effective as doctors and patients had been led to believe. Patients were more likely to get pregnant after getting Essure than after receiving a laparoscopic sterilization, he said.

“When we started presenting [patients] with the data, the number of Essure cases plummeted,” he noted.

Creinin, who has not implanted the device in years, said he thinks that Essure is not a bad product and that it is appropriate in certain cases. He isn’t even that troubled by the reports of side effects, which he said exist with any medical device. The problem, he said, is that Essure doesn’t work as well as Bayer suggests.

“I think the way the company provides information to [doctors] and patients is not the entire story,” he said. “The company’s goal is to sell its product.”

Angie Firmalino, a 43-year-old mother of four from Upstate New York, said she experienced relentless bleeding and severe abdominal pain two years after receiving an implant. It turned out that the Essure coils had broken apart and migrated to her uterus. She underwent several operations, including a hysterectomy.

In 2011, she created a Facebook group to alert others. “I wanted to warn other women,” Firmalino said. “Strangers just started finding it and posting their stories.”

The group now has more than 20,000 members, some of whom are heading to the FDA for Thursday’s hearing. Among them will be Kim Hughes, who is taking the day off from work and plans to testify about her experience.

“There are so many more [women] who are not able to be there, whether because of the cost or their physical issues or work,” Hughes said. “I’ve got to be able to give them a voice.”