More than 1,000 women across the United States have filed lawsuits against pharmaceutical giant Pfizer, alleging that its popular contraceptive injection, Depo-Provera, caused them to develop brain tumours.
The legal action follows the publication of new research linking prolonged use of the birth control drug to an increased risk of meningioma, a tumour that forms on the membranes surrounding the brain and spinal cord.
The lawsuits, filed in multiple states and consolidated into a multidistrict litigation (MDL) in Florida, claim Pfizer failed to warn users and healthcare providers about the potential danger.
What Is Depo-Provera?
Depo-Provera, also known as medroxyprogesterone acetate (DMPA), is a long-acting hormonal contraceptive injected every three months to prevent pregnancy. It has been widely prescribed for decades and remains a common choice among women who prefer not to take a daily pill.
Pfizer, which manufactures the drug, has faced growing scrutiny after several studies suggested a possible link between the use of DMPA and an elevated risk of developing meningiomas.
A 2025 study published in JAMA Neurology found that women who had used the injection for more than four years had nearly double the risk of being diagnosed with a meningioma compared with those who had never used it
Earlier research conducted in France and published in The BMJ reported a 5.6-fold increase in risk among women exposed to high doses of synthetic progestins like medroxyprogesterone acetate for over a year.
Legal Claims and Pfizer’s Response
The lawsuits accuse Pfizer of negligence, failure to warn, and product liability. Plaintiffs allege the company knew or should have known about the potential risk but failed to update the warning label on Depo-Provera. Some claim that despite emerging international evidence, Pfizer did not act swiftly to inform the public or healthcare professionals.
Pfizer has denied wrongdoing and argues that it complied with US Food and Drug Administration (FDA) regulations.
The pharmaceutical company also told The Post that they stand ‘behind the safety and efficacy of Depo-Provera, which has been used by millions of women worldwide and remains an important treatment option for women seeking to manage their reproductive health.’
In filings reported by Reuters, the company said the FDA rejected its attempt to add a tumour warning to the product label in 2023, citing a lack of conclusive evidence.
Pfizer’s legal team has also invoked the ‘preemption’ defence, asserting that federal law prevents the company from altering its product label without regulatory approval.
According to court records, more than 1,200 claims have been consolidated into a single MDL in the Northern District of Florida. The court has selected several ‘bellwether’ cases to test key issues such as causation and the preemption argument. The next case management hearing is scheduled for late October 2025.
Scientific Debate and Health Implications
While several studies have observed an association between Depo-Provera and meningioma, researchers stress that the findings do not prove causation. Meningiomas are typically benign and slow-growing, and the overall risk for users remains low.
However, prolonged use of high-dose progestins appears to heighten the likelihood of tumour development in some women.
The FDA has not issued new guidance regarding Depo-Provera, but regulators in Europe and Canada have updated product information to include warnings about possible brain tumour risks.
Medical experts continue to monitor new data as litigation progresses, urging women using the contraceptive to consult their healthcare providers before making changes to their treatment.
Originally published on IBTimes UK
