Updated

A $100 million settlement involving NuvaRing, a birth-control device linked to sometimes-fatal side effects, will stand now that the vast majority of claimants have chosen to opt into the agreement, those involved in the lawsuits said Thursday.

U.S. District Judge Rodney W. Sippel of St. Louis approved the settlement in February, but NuvaRing maker Merck & Co. had the right to abandon the deal if less than 95 percent of eligible claimants opted in.

The lead attorney for the claimants, St. Louis lawyer Roger Denton, said the 95 percent threshold has been reached, and the deal is now final. Merck, in a statement, confirmed that the agreement is final.

Denton said about 3,800 claimants will share in the settlement.

NuvaRing is a hormonal contraceptive inside a flexible ring that slowly releases two hormones into the vaginal wall: ethinyl estradiol, a type of estrogen that is widely used in contraceptives, and a progestin called etonogestrel. Merck has been selling NuvaRing since 2002.

The lawsuits allege faulty design and testing, and claim that the potential hazards of the device were not adequately disclosed.

Severe side effects connected to NuvaRing include blood clots, strokes and heart attacks, high blood pressure and heart disease, and cancer of the reproductive organs and breast. Denton said 83 wrongful death claims were part of the lawsuits.

"Hopefully we provide an awareness to the users of this product that just because they are FDA-approved does not mean they are necessarily safe for all users," Denton said. "People, particularly young women, need to be aware of this."

Merck, in its statement, said there is "substantial" evidence to show that NuvaRing is safe.

"We encourage women to work jointly with their health care providers to discuss the benefits and risks of any contraceptive method before choosing an option that is right for them," the company said.