Mirena IUD users may be at risk for pseudotumor cerebri, a side effect associated with the device’s active ingredient levonorgestrel.

Pseudotumor cerebri is the presence of brain tumor symptoms without an actual brain tumor. It’s also sometimes referred to as benign intracranial hypertension or idiopathic intracranial hypertension.

The most characteristic symptom is a headache that occurs daily or almost daily. Nausea, altered vision, and a sense of noises inside the head (called pulsatile tinnitus) may also occur.

The condition comes with a risk of blindness. Increased pressure inside the skull may lead to impingement of the optic nerve. This problem tends to manifest first as a loss of vision on the sides of the visual field.

As it progresses, the remaining vision may become blurry. Vision loss may only be partial, but some patients lose all vision in both eyes. And once the vision is lost, it tends not to come back, even if the pressure on the optic nerve is relieved.

Treatment for pseudotumor cerebri may require surgery. Doctors may install a permanent drain that channels excess cerebrospinal fluid from the brain to the stomach, relieving the pressure inside the skull.

The surgeon may also implant a structure called a stent to widen the channels through which CSF drains. Pressure on the optic nerve by making cuts along the outer covering of the nerve, is a procedure called optic nerve sheath fenestration.

What causes pseudotumor cerebri is not fully understood. It’s known that obese women of childbearing age are most at risk. The FDA has also issued warnings about particular pharmaceutical products that use the hormone levonorgestrel, the active ingredient in the Mirena IUD.

Mirena slowly releases levonorgestrel into the uterus, causing changes in the cervical mucus and uterine lining that prevent sperm from reaching the uterus and preventing fertilized eggs from implanting in the uterine wall. The device is designed to be implanted for five years at a time.

Mirena IUD Lawsuits

A set of federal Mirena IUD lawsuits has been consolidated into a single multidistrict litigation in the U.S. District Court for the Southern District of New York. Most of these claims are based not on pseudotumor cerebri but on other Mirena side effects, such as perforation of the uterine wall and migration of the device outside the uterus. Other plaintiffs report instances of pelvic inflammatory disease or ectopic pregnancy associated with their use of the Mirena device.

A small group of plaintiffs filed a petition for consolidation of claims specifically based on pseudotumor cerebri. But the federal Judicial Panel for Multidistrict Litigation denied their petition, saying that there were not so many such claims that consolidation would be worthwhile.

Another set of Mirena IUD lawsuits has been consolidated in a New Jersey state court. In all, over 1,600 such claims are now pending.

Bayer Pharmaceuticals, the maker of the Mirena IUD and the defendant in these Mirena IUD lawsuits, maintains that the benefits of Mirena continue to outweigh the risks.

The company also says it has disclosed all relevant information about the risks associated with Mirena since the FDA first approved it in 2000. The company maintains that the plaintiffs’ claims of failure to adequately warn about the risks are not based in fact.