Mirena Mirena IUD.

The U.S. Court of Appeals for the Second Circuit upheld Tuesday a summary judgment dismissing the multidistrict lawsuit against Bayer Pharmaceuticals, the manufacturer of the intrauterine birth control device Mirena.

In a summary order, a panel composed of Judges John Walker Jr., Jose Cabranes and Reena Raggi affirmed the decision by U.S. District Judge Cathy Seibel of the Southern District of New York to dismiss the suit after finding the plaintiffs’ expert witnesses were not credible.

The consolidated suit was brought before Seibel in 2013 on behalf of nearly 1,300 users across the country who said they were injured after the contraception Mirena was implanted. The suits alleged, among other things, negligence, strict liability and manufacturing defect on the part of Bayer.

The suit hinged on when, exactly, the injuries occurred. The parties agreed that injury to a woman’s uterus was possible during the contraception’s initial insertion phase. What was at issue was whether Mirena could later perforate and migrate from a uterus—something for which the drug company could potentially be liable.

In March 2016, Seibel issued an opinion and order excluding all three of the plaintiffs’ expert witnesses. The district judge found their testimony was unreliable, as none of them had done work around the issue prior to the trial, and all assumed the existence of the issue at question, and then “worked backwards to hypothesize a mechanism by which it might occur.”

In reviewing the decision, the panel Tuesday agreed in In Re: Mirena IUD Products Liability Litigation, 16-2890-cv, that Seibel had correctly applied the critical test for admitting expert testimony derived from the U.S. Supreme Court’s 1993 decision in Daubert v. Merrell Dow Pharm. The five-part test includes testability, prior peer review and publication, controlling standards, rate of potential error, and acceptance among a relevant scientific community.

The panel agreed that the theory of so-called secondary perforation has not been accepted in the “the wider obstetrics and gynecological scientific community.”

“Not only do the experts fail to identify any authorities that directly support the existence of secondary perforation, but what scientific authority there is casts doubt on the phenomenon’s existence,” the panel said.

Likewise, the panel found the experts lacked pre-litigation expertise in the subject they planned to speak to, and all assumed its existence, despite no literature in support of it and no prior research done by the experts.

The panel went on to back Seibel’s order granting the defendant’s motion to dismiss. State law controlled on the question of evidence in the suit, and every state in the union requires expert witnesses to prove causation in cases that had such complex medical device issues. Despite claims by defendants that the admissible evidence—including emails from employees noting reports of adverse events with the contraception and a warning label change by Bayer after the suit was filed—alone was enough for a jury, the panel agreed with Seibel that “the putative admissions proffered by plaintiffs are simply not enough to establish general causation.”

In a statement sent by Bayer spokesman Christopher Loder, the company said it was pleased with the panel’s decision.

“As we’ve always maintained, Mirena is an important reproductive health option for women, and this decision affirms that the company has at all times acted responsibly,” the company stated.

Bayer’s legal team was led by Arnold & Porter Kaye Scholer partner Lisa Blatt, who could not be reached for comment.

Parker Waichman appellate counsel Jay L.T. Breakstone represented the appellants. He could not be reached for comment.