Certain progestogen-based contraceptives increase the risk of meningioma, a rare brain tumor, according to a study of 3 million women published in JAMA Network Open. Researchers from the Danish Medicines Agency found the strongest link with the injectable contraceptive medroxyprogesterone (Depo-Provera), while the risk generally disappears within five years of stopping the medication.
How Progestogens Affect Meningioma Risk
Meningiomas are tumors that grow from the lining of the brain. According to reproductive endocrinologist Channa Jayasena of Imperial College London, these tumors often have receptors that “listen to” progesterone. This makes it plausible that synthetic compounds mimicking the hormone—known as progestogens—could trigger growth.
The Danish study indicates a tiered risk level based on the type of contraception used:
- Medroxyprogesterone (Depo-Provera): Showed the strongest association, with a relative risk increase of approximately 4-fold.
- Combined oral contraceptives and the “mini-pill”: Showed a weaker association, with a relative risk increase of 1.5-fold.
Absolute Risk vs. Relative Risk
While a “4-fold increase” sounds significant, cancer epidemiologist Paul Pharoah from Cedars-Sinai Health Sciences University notes the absolute risk remains tiny. In the general population, about 5 women per 1,000 will develop a meningioma in their lifetime.
For women aged 25 to 44 using medroxyprogesterone, that number only rises to 6 per 1,000. Pharoah emphasizes that these small increases must be balanced against the clinical benefits of contraception.
Comparing Medical Risks
Obstetrician and gynecologist Gino Pecoraro from the University of Queensland provides a contrast in risk profiles. He notes that while some contraceptives carry a small risk for meningioma, the Australian five-year survival rate following a meningioma diagnosis is greater than 90 percent. In contrast, maternal mortality in Australia is 6.6 per hundred thousand pregnancies.
Legal and Regulatory Responses
The link between hormonal birth control and brain tumors has moved from observational studies to legal and regulatory action. Since 2024, thousands of women diagnosed with intracranial meningiomas after using Depo-Provera have filed lawsuits against Pfizer.
Regulators have responded to this data. In December 2025, the US FDA approved a new label for the injection to warn customers about the possible connection to meningiomas. Simultaneously, the European Medicines Agency is conducting its own investigation into the association between progestogens and these tumors.
Clarification on Hormone Replacement Therapy (HRT)
The Danish data specifically targets contraceptives, not menopause treatments. Channa Jayasena clarifies that hormone replacement therapy uses much lower doses of progesterone than the contraceptives studied. Therefore, these findings do not apply to women taking HRT.
Frequently Asked Questions
Does the risk of meningioma last forever?
According to the Danish study, the elevated risk generally disappears within five years after a user stops taking contraceptive progestogens.
Which birth control has the highest associated risk?
The injectable contraceptive medroxyprogesterone (Depo-Provera) showed the strongest association, with a 4-fold relative risk increase.
Are these brain tumors cancerous?
Most meningiomas are benign in roughly 90 percent of cases, though they can still cause neurological symptoms if they press against brain tissue.
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