Depo-Provera: Risks, Studies & Legal Concerns

Depo-Provera is a widely used birth control injection that’s been on the market since 1992. According to Centers for Disease Control and Prevention data from 2015 to 2019, around a quarter of women who have had sex have used this medication.

The convenience of not needing a daily pill isn’t the only reason people may choose Depo-Provera. Health care providers may also recommend it for those who can’t take estrogen. It may also relieve endometriosis symptoms, such as cramping, and some users may stop having periods after a year of use. Periods typically return, though, when the user stops taking the medication. Patients with conditions that impact their menstrual cycles, such as anemia and uterine fibroids, have also been treated using Depo-Provera.

But there are risks associated with its use, with some users reporting life-altering complications.

Recent research has uncovered ties between prolonged Depo shot usage and the development of brain tumors.

What is a Meningioma, and Why is it Concerning?

A meningioma is a type of tumor that forms in the meninges, which are protective layers of tissue between the brain and the skull. According to Johns Hopkins, 30% of all brain tumors are meningiomas, making them the most common type of primary brain tumor.

Meningiomas are generally benign, meaning they are not cancerous. But they can still have devastating effects.

The tumor’s effects can vary by location and size. Meningioma symptoms may range from headaches and dizziness to vision loss and seizures. Symptoms may worsen as the tumor grows and begins to press onto the brain, nerves or blood vessels.

According to the Mayo Clinic, meningiomas may grow over several years without symptoms. However, a symptomatic or large meningioma has the potential to cause severe disability.

Treatment of meningiomas varies by the tumor’s location, effects and other factors. If the meningioma is small and asymptomatic, a doctor may suggest an observation approach. However, a large or symptomatic meningioma is often treated by surgery or radiation.

While surgery may be necessary to remove a meningioma, these procedures can be challenging and do not always solve the problem. Sometimes, patients are left with complications or serious neurological issues, such as depression or seizures.

What Studies Link Depo-Provera to Meningioma?

Concerns involving Depo-Provera’s ties to meningiomas began to emerge after a French study was published in the BMJ in February 2024.

The study analyzed data from tens of thousands of women. The researchers found that people using drugs like Depo-Provera are much more likely to develop a meningioma. This risk is higher in Depo users than for those who used other birth control methods or none at all.

The researchers also determined that risk increased with long-term use.

This connection could be partly due to how meningiomas react to certain hormones. Meningiomas often have progesterone receptors, meaning the tumor likely interacts with that hormone. Depo-Provera contains progestin, a synthetic version of the progesterone hormone, that meningiomas may be reacting to. However, the exact mechanism or effect of this interaction is unclear.

Another study conducted by researchers at the University of British Columbia similarly suggested that users of Depo-Provera are at an increased risk of developing meningiomas. The researchers noted that their study accounted for how long meningiomas can take to grow. This likely reduced the chance that pre-existing meningiomas influenced the results.

The researchers also noted that people who are concerned about meningiomas should consider Depo-Provera alternatives like birth control pills that contain estrogen.

Who Is Most at Risk for Developing Meningioma?

The study published in the BMJ determined that those who have used Depo-Provera for a prolonged period could be at notably higher risk of developing meningiomas. The study defined prolonged use as being at least one year or more.

Like other birth control methods, it is common for users to take Depo-Provera for many years.

Outside of depo usage, gender also plays a big role in determining who is at risk of developing a meningioma. According to the Cleveland Clinic, women are twice as likely as men to develop this type of tumor, probably because of the hormones related to their development. Men, however, are more likely to develop malignant meningiomas.

Further, women who have used birth control pills or hormone replacement therapy may be at additional risk of developing meningioma. While Depo-Provera had the highest correlation with meningioma development, a large study published in BMJ also found a small risk with birth control ingredients medrogestone and promegestone.

The Cleveland Clinic also reports that Black people, adults 65 or older or people with a parent or sibling who has had a meningioma are at particular risk. A history of breast cancer or radiation to the head may also be risk factors.

Other Common Depo-Provera Side Effects and Long-Term Risks

In addition to potential concerns involving meningiomas, there are several other more common Depo-Provera side effects to be aware of.

The Depo shot has also been linked to medical concerns like migraines, depression, seizures, ectopic pregnancy, blood clots, stroke and other serious issues.

In addition to the above, Depo-Provera’s current packaging warns users of the potential for significant bone density loss. The warning notes that density loss could be worse with prolonged use of the drug, and full recovery is not guaranteed.

Questions have emerged regarding whether Pfizer, which manufactures Depo-Provera, was ever aware of the drug’s potential links to meningiomas. However, connections between meningiomas and sex hormones relevant to Depo-Provera have been observed since the 1920s.

Further, in some countries, the Depo-Provera box has had warnings about meningiomas for years. The U.S. version of Depo-Provera has never included any reference to a risk of meningiomas, which is one of the points raised by the lawsuits.

How Have Governments Responded to Depo-Provera’s Risks?

Depo-Provera lawsuits claim that the Canadian label of the drug has listed meningiomas under “post-market adverse drug reactions” for over 10 years. Labels in the United Kingdom and European Union also include information regarding meningiomas.

If you have taken Depo-Provera and are experiencing symptoms associated with meningiomas, you may consider consulting a doctor. This is especially true if the symptoms have gotten more obvious over time, as meningiomas are slow-growing. Early symptoms can include headaches that continue to worsen as time passes, along with vision issues.

According to Penn Medicine, when a doctor suspects a meningioma, they will likely refer you to a neurologist. The specialist then conducts a neurological exam followed by CT scans or MRIs. They may also take a biopsy to verify the diagnosis.

Legal Implications of Depo-Provera and Meningioma

Many lawsuits have already been filed over claims that Pfizer failed to warn of the potential meningioma risk tied to the use of Depo-Provera.

In February, more than 70 Depo lawsuits were consolidated in multidistrict litigation (MDL) before one judge, setting the stage for a streamlined and expedient litigation process.

The MDL involves claims from women who took Depo-Provera and were later diagnosed with a meningioma. Litigation will likely focus on whether Pfizer should have warned its customers of these potential risks.

If you developed a meningioma after taking Depo-Provera, you may be able to file a lawsuit. You can sign up for a free case review and connect with an experienced product liability lawyer through Drugwatch.

Editor Lindsay Donaldson contributed to this article.