Nearly a hundred women have united to file a single mass tort lawsuit over Essure contraception side effects.

The claim, filed in a Missouri state court in St. Louis, names as defendants Bayer Inc. and its related companies, all of whom are allegedly involved in the design, manufacture or marketing of Essure birth control implants.

The 95 plaintiffs claim to have Essure contraception side effects caused by alleged flaws in Essure implants that they say make the implants a “defective and unreasonably dangerous product.”

According to the Essure lawsuit, an Essure implant consists of a stainless steel inner coil, an outer coil made from a nickel-titanium alloy and a layer of fibers between the two coils.

To implant Essure, a physician places one such implant in each fallopian tube. The implants stimulate growth of new tissue that over the course of a few months blocks the fallopian tube, preventing fertilization.

In particular, the plaintiffs take issue with Bayer Essure Inc., formerly known as Conceptus Inc. Conceptus was the company that originally designed Essure back in 1998, the plaintiffs say. Bayer eventually bought Conceptus, and with it the rights to Essure, in 2013.

The women allege that Conceptus developed Essure solely out of business concerns and with inadequate concern for the fallout from Essure contraception side effects.

According to their Essure lawsuit, at the time Conceptus began working on Essure, the company was hundreds of millions of dollars in debt.

With an estimated 700,000 women undergoing tubal ligation every year, Conceptus saw a business opportunity in presenting that market with a non-surgical alternative for permanent birth control.

The plaintiffs say Conceptus developed Essure to respond to that opportunity and to resolve its massive debt problems, with little regard for patient safety.

FDA Warns of Essure Contraception Side Effects

In February 2016, the FDA ordered the addition of a black box warning to Essure’s label. The new warning advises that some patients have reported “perforation of the uterus and/or fallopian tubes, intra-abdominal or pelvic device migration, persistent pain, and allergy or hypersensitivity reactions” after being implanted with Essure.

This new warning addresses the Essure contraception side effects that the plaintiffs say Conceptus unlawfully hid from the FDA and the public.

They claim thousands of patients have complained directly to the defendants about adverse effects. Conceptus withheld these complaints from the FDA, even though it was obligated under federal law to report them, the plaintiffs say.

For example, plaintiffs say the company was aware of hundreds of instances in which an Essure implant broke after implantation, allegedly receiving 462 such reports between May 2014 and January 2016.

Yet the company repeatedly reported to the FDA that there were only single cases of breakage, the plaintiffs say.

Instead of divulging the reported adverse events, plaintiffs say, Conceptus conducted an aggressive marketing campaign that the plaintiffs say contained false and misleading statements about Essure’s safety and efficacy.

“Conceptus engaged in substantial, widespread and systemic false, misleading and illegal promotional activities to encourage physicians and patients to use the Essure device,” the plaintiffs allege. They say Conceptus was cited by the FDA several times for withholding safety information.

The Essure Contraception Side Effects Lawsuit is Case No. 4:16-cv-01189 in the U.S. District Court for the Easter District of Missouri.