A new study from Case Western Reserve University School of Medicine and Cleveland Clinic has found that using a specific type of birth control—depot medroxyprogesterone acetate, or dMPA—may raise the risk of developing meningioma, a type of non-cancerous brain tumor.
The study focused on U.S. women and found that the risk increased significantly with longer use or when the drug was started later in life.
Meningiomas are slow-growing tumors that develop in the membranes surrounding the brain and spinal cord. They are the most common type of primary brain tumor in the United States and are more likely to occur in women than in men.
Because of this gender difference, researchers have long suspected a connection to hormones like estrogen and progesterone. Many meningiomas contain receptors for these hormones, especially progesterone.
Depot medroxyprogesterone acetate is a synthetic form of progesterone used in birth control shots, as well as in treating issues like abnormal bleeding and endometriosis.
Previous studies in France and the U.S. had already hinted at a possible link between this drug and meningioma risk, but this new research provides some of the strongest evidence yet.
Published in JAMA Neurology, the study looked at medical records from more than 10 million women in the U.S. health system between 2004 and 2024. Researchers compared users of dMPA with women using other forms of birth control, such as oral pills, IUDs (intrauterine devices), and implants.
They found that women who used dMPA had a 143% higher risk of being diagnosed with meningioma compared to women who didn’t use it. That means the rate of diagnosis was more than double—7.39 cases per 100,000 women each year, compared to just 3.05 in those who didn’t use dMPA.
The longer women used the birth control shot, the greater their risk. Women who used it for four to six years had a 200% higher risk, while those who used it for more than six years had a 290% higher risk.
Age also made a difference. Starting dMPA between ages 31 and 40 increased risk by 277%, starting between 41 and 50 increased it by 175%, and starting after 50 led to a 220% higher risk.
The study also looked at other forms of hormonal birth control. Oral medroxyprogesterone acetate, a similar drug taken by mouth, was linked to an 18% higher risk. But other types of birth control, including combined oral contraceptives, IUDs, and implants, were not linked to higher meningioma risk.
In fact, some of them were associated with a lower risk. For example, combined oral contraceptives were linked to a 26% lower risk, and IUDs overall were linked to a 13% lower risk.
The researchers say these findings are important for women and doctors to consider when choosing a birth control method, especially for long-term use or for women starting birth control later in life.
While meningiomas are not cancerous, they can still cause serious health problems depending on their size and location in the brain. Regular monitoring and informed decision-making may help reduce these risks.
The study is published in JAMA Neurology.
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