Bayer faces a new lawsuit alleging that Mirena headaches from pseudotumor cerebri were an unwarned side effect.

On April 26, Plaintiff Mary W. filed her lawsuit against Bayer Healthcare Pharmaceuticals Inc., Bayer Pharma AG, and Bayer OY. She claims that she developed pseudotumor cerebri and Mirena headaches after using the levonorgestrel IUD.

The Mirena is an IUD which releases levonorgestrel, a synthetic form of the hormone progestogen. The synthetic chemical affects the female reproductive system to prevent conception.

Although the exact mechanism of progestogen and levonorgestrel is unknown, a fact allegedly admitted by Bayer, the hormones are thought to thicken cervical mucus which inhibits sperm movement. The device can be inserted into the uterus during an office visit and is effective for five years, although it is not suggested for women that have not had a child.

According to Mary’s complaint, she had the Mirena implanted in February 2017. After receiving the implant, she says, she developed papilledema in both eyes, optic nerve edema, intercranial hypertension (also known as pseudotumor cerebri), and chronic Mirena headaches.

To treat her resulting issues, Mary says she had to have medical care including lumbar puncture and MRI. Since her treatment, she had continued to suffer from abnormal uterine bleeding, Mirena headaches, tingling in feet, papilledema in both eyes, and optic nerve edema.

The experience Mary reports with the Mirena IUD are not unique. Many women have reported similar symptoms, all thought to be caused by pseudotumor cerebri. Research suggests that levonorgestrel, the active hormone in the Mirena, causes the body too to produce too much cerebrospinal fluid, leading to the development of tumor-like symptoms which give the condition its name.

Pseudotumor cerebri is a condition involving an abnormal amount of cerebrospinal fluid in the skull. The excess of fluid builds up in the skull and causes increased pressure, mimicking the symptoms of a brain tumor.

Symptoms of pseudotumor cerebri include migraines, tinnitus, blurred vision, double vision, temporary blindness, blind spots, and other visual problems. The visual side effects of pseudotumor cerebri are thought to result from increased pressure on the optic nerve. Failure to diagnose and treat pseudotumor cerebri may lead to permanent damage to the optic nerve, resulting in vision loss or partial blindness. There is no treatment to reverse such damage.

Mary argues that Bayer has not properly warned patients and physicians of the risk associated with pseudotumor cerebri and Mirena headaches.

“Despite a wide body of information available to Defendants regarding the connection between levonorgestrel and [pseudotumor cerebri], Mirena’s label is devoid of any warning regarding [pseudotumor cerebri],” the lawsuit states.

Mary claims that Bayer is liable for her medical expenses and emotional pain because the did not warn consumers of potential Mirena headaches and other side effects, meaning she could not make an informed decision.

Mary accuses Bayer of negligence, design defect, failure to warn, strict liability, breach of warranty, negligent misrepresentation, fraudulent misrepresentation, fraud, and violation of state consumer fraud violations. Mary seeks compensatory damages, punitive damages, court costs, and attorneys’ fees.

The Mirena Headaches Lawsuit is Case No. 7:18-cv-03687 in the United States District Court for the Southern District of New York.