Hundreds of women in the US and the UK suing the big pharma giant over a contraceptive jab that has put them at risk of a potentially fatal brain tumors.

In the UK, NHS data shows that approximately 10,000 prescriptions are handed out every month for medroxyprogesterone acetate, known under the brand name Depo-Provera.

Legal documents filed against Pfizer allege that they knew that patients were at an increased risk of developing the dangerous tumors, particularly after prolonged use of Depo-Provera.

Catholic News Agency reports: A case management conference regarding the multi-district litigation was held on May 30 in Pensacola, Florida, to discuss the next steps in the lawsuits filed against New York-based Pfizer. 

The legal action follows a 2024 French study that found that the use of the contraceptive medication medroxyprogesterone, often known under Pfizer’s brand name Depo-Provera, renders a woman five times more likely to develop a meningioma brain tumor.

Meningiomas are slow-growing tumors that are usually benign but can cause severe injury or death if they become large enough to compress the brain or spinal cord.

The research study conducted by the National Agency for Medicines and Health Products Safety examined data on 18,061 women. The participants were on average around 57 years old and had all undergone intracranial surgeries for meningiomas between 2009 and 2018. 

The observational study found that women who had used progestational hormones including medrogestone, medroxyprogesterone acetate, or promegestone for a year or longer had a heightened risk of suffering from a meningioma that required surgical intervention.

The research showed that the risk of developing a meningioma tumor was 5.6% higher among women who had used Depo-Provera.

After the study was released, Pfizer acknowledged the “potential risk associated with long-term use of progestogens.” The company said it was working to update “product labels and patient information leaflets with appropriate wording,” but as of 2025 the drug still does not have a written warning in the United States.

According to a press release filed on behalf of the roughly 400 plaintiffs, “the lawsuits allege that Pfizer and other generic producers of Depo-Provera were aware of the link between these birth control injections and brain tumors and that they failed to adequately warn of the risk and promote safer alternatives.”

Women in the United Kingdom are also starting to take legal action against pharmaceutical companies that have issued the drug. According to Britain’s National Health Service, in the U.K. about 10,000 women receive an injection of the contraceptive every month.