The Food and Drug Administration has ordered Bayer to conduct a 2,000-patient postmarketing study of the Essure implantable birth control device, to explore the risks it may pose to some women and examine how it is being employed in clinical practice.

Bayer, which manufactures the device, will also be required to add a boxed warning to the label, describing potential adverse events, and a “Patient Decision Checklist” to help guide preimplantation discussions, under draft guidance issued by the FDA on Feb. 29.

The 3-year observational study will compare data on complications, pregnancy, and pregnancy loss in Essure patients and in women who undergo bilateral tubal ligation, according to Dr. William Maisel, chief scientist at the FDA’s Center for Devices and Radiological Health.

“This will be a large observational study,” he said during an FDA press briefing on Feb. 29. “The specific questions will relate to overall complications rates; perforation, migration, and expulsion; chronic pelvic pain; abnormal uterine bleeding; allergy and hypersensitivity,” and obstetric outcomes.

Because FDA is requiring such a large patient cohort with long-term follow-up, final study results will be years away. Therefore, Bayer will be required to release data intermittently to keep the public well informed as research progresses, Dr. Maisel said.

The requested study will also examine why some patients don’t have a confirmation test to ensure that Essure has been properly placed 3 months after insertion – a key area that seems related to a number of reported adverse events, including pregnancy and device migration.

Despite the push for additional data, the FDA still believes that Essure is an appropriate and safe permanent option for the majority of women who want permanent birth control, Dr. Maisel said.

“It’s the only nonincisional form of permanent birth control. It requires no general anesthetic to insert, and most women go back to work in a day,” he said. “It is highly effective at preventing pregnancy, and it contains no drugs or hormones. Essure should remain an option for women seeking permanent birth control who are informed of its risks.”

Bayer officials said they will continue to work closely with the FDA to support the safe and effective use of the device.

“Patient safety and appropriate use of Essure are our greatest priorities,” Dr. Dario Mirski, senior vice president and head of medical affairs Americas at Bayer said in a statement. “A woman’s decision to choose a birth control method is a very important and personal one, and Bayer is committed to providing physicians with resources, tools, and information to help them counsel women about Essure.”

The boxed warning announced by the FDA will outline the adverse events that may be associated with Essure, including those that might occur during insertion and removal. The “Patient Decision Checklist” will be designed to help doctors stress the importance of the 3-month confirmation test to determine that it is correctly placed and that sufficient scar tissue has formed to prevent pregnancy. Both patient and physician will have to sign off on the checklist before the device is employed.

The FDA is seeking public comments on the proposed language for the warnings. The docket will be open for 60 days.

“The actions we are taking today will encourage important conversations between women and their doctors to help patients make more informed decisions about whether or not Essure is right for them,” said Dr. Maisel. “They also reflect our recognition that more rigorous research is needed to better understand if certain women are at heightened risk of complications.”

The draft guidance solidifies discussions that occurred last fall during a meeting of the FDA Obstetrics and Gynecology Devices Panel. During that meeting , the 19-member panel heard testimony from dozens of women who developed pain and other serious problems, including autoimmune diseases, after receiving Essure.

Since the device was approved in 2002, the FDA has received more than 5,000 complaints of such adverse reactions. These include 631 pregnancies and 294 pregnancy losses.

Between the September meeting and the FDA’s draft guidance announcement, the agency has received even more information from patients. A 22,000-person support group called Essure Problems collected and submitted a large amount of personal and clinical data. The package was submitted to the FDA on Feb. 22 and includes surgical notes and photos; letters from doctors and surgeons; pregnancy records; data on fetal death, ectopic pregnancies and miscarriage; and a series of electromicrographic images purporting to show defects of the coils’ metal ribbons.

The administrators of the Essure Problems groups blasted the FDA for requiring studies, rather than removing the device from the market. “These studies could take several years, and leaving the device on the market will only put more women’s lives at risk,” they wrote .

Rep. Mike Fitzpatrick (R-Pa.), who has been critical of Essure, said that the FDA’s actions are inadequate and said he will push for congressional action , including blocking government agencies from purchasing the device and revoking the FDA’s approval of Essure.