Feb 29 (Reuters) - Bayer AG's Essure birth control implant should carry the strongest safety warning label, U.S. regulators said on Monday, following thousands of complaints about the device.
The U.S. Food and Drug Administration also asked the German drugmaker to conduct a post-market study of the device.
Essure, acquired by Bayer in 2013, has been the target of complaints and calls for its withdrawal since it was approved for sale in the United States in 2002.
FDA said it intends to require the product to carry a "black box" label warning of serious risks such as perforation of the uterus or fallopian tubes and severe allergic reaction. It is asking the public to submit comments on the language to be included in the label warning.
The device, promoted as an alternative to tubal ligation for permanent birth control, consists of two small nickel-titanium coils inserted into the fallopian tubes. Scar tissue that forms around the device is meant to prevent pregnancy.
Complaints have included reports of the device breaking, moving and causing side effects ranging from chronic pain and bleeding to autoimmune disorders such as psoriasis and lupus.
The agency also issued a checklist for doctors to use in discussing the risks with patients and instructed Bayer to conduct a clinical study to further assess the product's safety and effectiveness.
"The agency continues to believe the product should remain available to women who are informed of the risks," Dr. William Maisel, deputy director for science in the FDA's center for devices and radiological health, told reporters on a call.
The post-market study will enroll more than 2,000 women who will be followed for a minimum of three years and will compare the Essure implant to tubal ligation, Maisel said.
Bayer said it would work with the FDA, while reiterating the positive benefit-risk profile of Essure.
Many members of a 27,000-member Facebook group "Essure Problems" expressed disappointment at the FDA's announcement. The group, as well as consumer watchdog Public Citizen, has been pushing for a ban on the device.
"The FDA unacceptably puts patients at risk by allowing the device to continue to be marketed as this surveillance study proceeds," Sarah Sorscher, an attorney for Public Citizen, said in an email.
Bayer estimates there are about 750,000 women using Essure worldwide, about 70 percent of them in the United States.
More than 5,000 adverse events involving Essure have been reported, according to the FDA's website, although the role of the device is not always clear.
Related: See the history and evolution of birth control:
The evolution of birth control
FDA calls for strongest warning on Essure birth control device
Closeup still life of Zorane tablets, a series of low-estrogen birth control pills. Shown are three packs, one open, two closed. (Photo by Hulton Archive/Getty Images)
Various big posters were hoisted in Saint Peter's Square by a group of persons favoring artificial birth control, as Pope Paul VI appeared in the central balcony of Saint Peter's Basilica to read his Easter message to the world and impart his blessing "Urbi et Orbi" (Over the City of Rome and the World) March 26, 1967. The huge poster in center reads: "Yes to the pill", while others read: "No to Abortion." (AP-PHOTO)
13th August 1968: Father Paul Weir expounds on his refusal to quit the Catholic church in the St Cecilia Presbytery in North Cheam. Father Paul, 31, was suspended from his duties because he disagrees with the Pope's ruling on birth control. (Photo by Keystone/Getty Images)
Birth control advocate Bill Baird, center, and Carol Morreale, left, as they led a demonstration outside the Immaculate Conception Church, Aug. 18, 1974 in Marlboro, Mass., protesting the denial of the baptismal sacrament to 3-month-old Nathaniel Morreale. Carol Morreale, the child's mother has publicly advocated that women be given the right to choose whether they will have an abortion. (AP Photo)
A woman holds a birth control pill dispenser indicating the day of the week in New York in August 1974. Though medical trials for the oral contraceptive started in the late 1950s, Enovid was approved by the Food and Drug Administration in 1960. The sexual revolution was born. Known as "The Pill," it changed the balance of hormones estrogen and progesterone in women to prevent pregnancy. It was invented by Dr. Gregory Pincus and Dr. John Rock with the support of Planned Parenthood founder Margaret Sanger. (AP Photo/Jerry Mosey)
FILE - This May 28, 1999, file photo shows a new birth control pill container designed to look like a woman's makeup compact for Ortho-McNeil Pharmaceutical Inc., of Raritan, N.J., displayed at the manufacturer's assembly line. More than half of privately insured women are getting free birth control due to President Barack Obamaâs health care law, part of a big shift thatâs likely to continue despite the Supreme Court allowing some employers with religious objections to opt out. (AP Photo/Mike Derer, File)
Graphic shows the Implanon implant, with contraceptive use stats among women ages 15-44. (AP Graphic)
Graphic shows preferred method of birth control for women by age; 1c x 3 1/2 inches; 46.5 mm x 88.9 mm
Chart shows failure rate of popular female contraceptives
Graphic shows the annual cost of the most effect birth control methods
Individually packaged hand-knitted uteri are placed on a countertop at the lobby of the State Capitol in Phoenix, Thursday, April 5, 2012. Critics of an Arizona proposal to limit birth control gave more than a dozen state lawmakers the personalized gift. The packages were delivered each in a clear plastic bag, labeled with a lawmakerâs name and containing a letter from a Tempe woman asking legislators to oppose the measure. (AP Photo/Terry Tang)
FILE - In this May 2, 2013 photo, pharmacist Simon Gorelikov holds a generic emergency contraceptive, also called the morning-after pill, at the Health First Pharmacy in Boston. The plaintiffs in a legal battle over emergency contraceptives say in a letter Wednesday June 12, 2013, the government has failed to comply with a New York judge's order to lift all restrictions on sales of the drug. (AP Photo/Elise Amendola, File)
A group of people organized by the NYC Light Brigade and the women's rights group UltraViolet, use letters in lights to spell out their opinion, in front of the Supreme Court, Monday, March 24, 2014, in Washington. Holding the "H" in "Hands" is Rep. Keith Ellison, D-Minn. The Supreme Court is weighing whether corporations have religious rights that exempt them from part of the new health care law that requires coverage of birth control for employees at no extra charge. (AP Photo/Alex Brandon)
Margot Riphagen of New Orleans, La., wears a birth control pills costume as she protests in front of the Supreme Court in Washington, Tuesday, March 25, 2014, as the court heard oral arguments in the challenges of President Barack Obama's health care law requirement that businesses provide their female employees with health insurance that includes access to contraceptives. Supreme Court justices are weighing whether corporations have religious rights that exempt them from part of the new health care law that requires coverage of birth control for employees at no extra charge. (AP Photo/Charles Dharapak)