Amid Lawsuits, Experts Caution More Research Into IUDs Causing Neurological Disorder

Over the past two years, 856 people have filed lawsuits against German drug company Bayer, claiming that the popular IUD Mirena is causing neurological side effects, Rewire reports. Experts who have been following the case, however, say that more research is needed before a connection can be made between the contraceptive and the disorder addressed in the complaint.

FDA spokesperson Deborah Kotz told Rewire News no conclusions can be drawn about Mirena’s link to the disorder just yet. “Existence of a report does not establish causation,” she said. “For any given report, there is no certainty that a suspected drug caused the reaction.”

In a statement to Refinery29, Bayer asserted that they are continuing to work with the FDA. The legal case is ongoing. “Bayer takes all adverse events seriously, continually collects and analyzes the data we receive. We work closely with the FDA to monitor Mirena’s safety profile, and based on the totality of data available to date, a positive benefit-risk profile consistent with approved labeling continues to be observed with Mirena. To date, no study, physician, or regulatory agency has concluded that Mirena can cause idiopathic intracranial hypertension (IIH). Judge Engelmeyer, in a recent decision excluded all the expert witnesses presented by plaintiffs, stating that ‘[o]utside of this litigation, there is a complete absence of scholarship opining that Mirena, or for that matter any LNG-based contraceptive, is a cause of IIH.’ In light of this decision, the Court has invited motions for summary judgment from Bayer."

Mirena is a tiny piece of T-shaped plastic that is inserted directly into the uterus as a way to prevent pregnancy. The FDA approved the sale of Mirena in the United States in 2000, and it is now considered one of the most popular IUDs in the country; 2 million women use it worldwide.

Side effects of the device are not unlike the side effects found with any contraceptive: weight gain, nausea, cramping, or abdominal and pelvic pain, to name a few. IUD-specific side effects such as expulsion or perforation are also possible, and listed directly on the product label.

That complaint lodged in this most recent set of lawsuits pertains to something that is not listed on the label: a neurological disorder that falsely resembles a tumor. The disorder is known as pseudotumor cerebri, or idiopathic intracranial hypertension — a fancy way to say increased pressure on the brain. The Mayo Clinic lists symptoms of the condition as including headaches, worsening vision, tinnitus, ringing in the ears, and nausea. At present, the cause of the disorder is unknown, though factors like obesity, some medications, and various health problems are among the risk factors.

This story was originally published on December 8, 2018. It has been updated with additional reporting.