A Common Contraceptive Tied to Rare Brain Tumors in Study

One injection. Three months of protection. And for a small number of women, a question that has echoed through courtrooms and clinics: can a widely used contraceptive raise the risk of a rare brain tumor?

Researchers in Denmark went looking for answers in an extraordinary archive — 25 years of health records covering roughly three million women. Their analysis, published in JAMA Network Open, does something few earlier studies managed: it teases apart different hormonal products and links the risk specifically to certain progestogen formulations rather than to all hormonal contraception.

The headline finding was sharp and specific. Medroxyprogesterone acetate — the injectable commonly known by the brand Depo‑Provera — showed the strongest association with meningioma, with a roughly fourfold relative increase in risk while used. Combined oral contraceptives and progesterone‑only pills showed smaller associations, close to a 1.5‑times relative increase. Crucially, the elevated risk appeared to vanish within about five years after stopping the progestogen.

Numbers like “fourfold” sound alarming. So context matters. Cancer epidemiologist Paul Pharoah of Cedars‑Sinai points out that meningiomas are uncommon: about five women per 1,000 develop one across a lifetime. In the Danish data, medroxyprogesterone use during ages 25–44 nudged that to approximately six per 1,000.

The absolute chance remains small, but it is real — and it should be weighed against contraceptive benefits on an individual basis.

Meningiomas arise from the brain’s protective lining. Most are benign — roughly nine out of ten — and many are managed successfully with surgery or radiation. Yet when they grow in sensitive locations they can cause seizures, vision problems, or cognitive changes, which is why any increase in risk draws attention from both clinicians and regulators.

Why the link? Hormones are the usual suspects. Meningiomas frequently carry receptors that respond to progesterone, and the tumors sometimes enlarge during pregnancy or when people receive progesterone‑like medications. Reproductive endocrinologist Channa Jayasena has long noted this biologic plausibility: if a tumor can ‘listen’ to progesterone, then exposure to synthetic progestogens could, in some cases, prompt growth.

The study’s timing adds fuel to an ongoing debate. Thousands of patients who developed intracranial meningiomas after receiving Depo‑Provera injections have pursued legal claims, and in December 2025 the U.S. Food and Drug Administration approved revised labeling for the injection warning of a possible connection. The European Medicines Agency is also examining the association.

Clinicians responding to the new evidence urge nuance. Obstetrician‑gynecologist Gino Pecoraro highlights the tradeoffs: contraception prevents unwanted pregnancies and their real, measurable risks; for example, maternal mortality and pregnancy‑related complications remain serious considerations. Others, including gynecologist Melanie Davies, emphasize that because meningioma is rare these findings should not automatically drive women away from progestogens that effectively treat both contraception and other debilitating conditions.

There are limits. The Danish analysis was strong in scope, but it was observational; it can show association, not definitive cause. It also focused on contraceptive doses and formulations, not on hormone replacement therapy at the much lower doses used for menopause management, so HRT shouldn’t be conflated with the contraceptive exposures in this study.

What should patients do now? Discuss. Ask questions. If you use or prescribe medroxyprogesterone or other progestogen products, consider personal risk factors, alternatives, and the timing of use. Don’t stop a prescribed method without medical advice — sudden changes carry their own consequences.

Science rarely hands us absolute answers. This study narrows the view and points clinicians to where caution and conversation are warranted — and where future research should focus.