Depo-Provera Linked to Brain Tumors — Women Sue Pfizer

Thousands of women across the United States are suing Pfizer, the manufacturer of Depo-Provera, alleging the injectable birth control shot caused them to develop meningioma brain tumors. The lawsuits claim Pfizer knew for decades that medroxyprogesterone acetate, the synthetic hormone in Depo-Provera, could stimulate the growth of hormone-sensitive tumors in the brain — and said nothing. The first U.S. warning did not appear until December 2025, more than 30 years after the drug was approved as a contraceptive.

The federal litigation is consolidated in MDL No. 3140, Depo-Provera (Depot Medroxyprogesterone Acetate) Products Liability Litigation, in the U.S. District Court for the Northern District of Florida before Judge M. Casey Rodgers. As of May 2026, over 5,500 cases have been filed in the MDL alone, with hundreds more pending in state courts in Delaware, New York, California, and elsewhere. A critical Daubert hearing on general causation is scheduled for June 24 to 26, 2026, which will determine whether plaintiffs’ scientific experts can testify before juries — and whether the first bellwether trials can proceed in December 2026.

Lawsuit Timeline and Updates

1983 — Science Identifies Progesterone Receptors in Meningiomas

The biological case against Depo-Provera begins in 1983. A study published in the European Journal of Cancer & Clinical Oncology found that meningioma cells contain a high concentration of progesterone receptors. If progesterone drives these tumors, synthetic versions of the hormone could too. Plaintiffs’ attorneys will argue that this publication gave pharmaceutical companies their first scientific signal — and that Pfizer’s predecessors ignored it for four decades.

1989 to 1991 — Anti-Progesterone Research Confirms the Mechanism

Follow-up research between 1989 and 1991 tightened the biological case. Studies in the Journal of Steroid Biochemistry and the Journal of Neurosurgery found that blocking progesterone with mifepristone caused meningioma cells to shrink. The reasoning is direct: if blocking the hormone stops tumor growth, then adding synthetic progesterone through an injectable drug could start it. Pfizer’s predecessor, Upjohn, was already marketing Depo-Provera internationally by this point. No meningioma warning was added.

1992 — FDA Approves Depo-Provera as a Contraceptive in the U.S.

The FDA approved Depo-Provera as a contraceptive in 1992, after decades of regulatory controversy. Prior applications in 1967, 1978, and 1983 had been denied, partly over cancer concerns. The 1992 approval came with warnings about bone density loss and other risks. No meningioma warning was required or included. The drug was marketed as a convenient, highly effective contraceptive requiring only one injection every three months. Over the following decades, Upjohn merged with Pharmacia in 1995, and Pfizer acquired Pharmacia & Upjohn in 2002, inheriting full responsibility for the drug and its label.

Before 2024 — Europe and Canada Warn; U.S. Does Not

Before the 2024 research wave, European and Canadian regulators required Pfizer to add meningioma warnings to Depo-Provera labels in their jurisdictions. The EU label stated that meningiomas had been reported following long-term administration and that the drug should be discontinued if a meningioma is diagnosed. The same warning did not appear on U.S. labels. Women in the United States received a different — and materially less complete — picture of the drug’s risks than women in Europe and Canada.

March 2024 — BMJ Publishes Landmark French Study

In March 2024, a major study published in the British Medical Journal changed the litigation landscape. French researchers analyzed data from 108,366 women, including 18,061 who underwent surgery for meningioma, drawn from the French National Health Data System. Among users of medroxyprogesterone acetate (MPA, the active ingredient in Depo-Provera), the odds ratio for developing meningioma was 5.55. That means long-term users were more than five times more likely to develop this type of brain tumor than non-users.

An odds ratio of that magnitude is extraordinary in pharmaceutical litigation. The study triggered the wave of lawsuits now pending across the country. Plaintiffs’ attorneys began filing claims almost immediately after publication.

October 2024 — First Lawsuits Filed, MDL Process Begins

The first Depo-Provera meningioma lawsuit was filed in October 2024 by a woman who had used the drug between 2005 and 2021. Additional lawsuits followed rapidly as law firms began investigating the claims. The Judicial Panel on Multidistrict Litigation took notice of the growing docket.

February 7, 2025 — Federal MDL Established in Florida

On February 7, 2025, the Judicial Panel on Multidistrict Litigation centralized all federal Depo-Provera meningioma lawsuits into MDL No. 3140, assigned to Judge M. Casey Rodgers in the Northern District of Florida. The Panel found that the cases shared common questions of fact: whether Depo-Provera causes meningioma, whether Pfizer knew of the risk, whether it failed to warn, and whether it failed to promote a safer alternative in Depo-SubQ Provera 104, a lower-dose formulation. Centralization would eliminate duplicative discovery and prevent inconsistent pretrial rulings across districts.

September 2025 — Cleveland Clinic Study Strengthens Science

A study published in JAMA Neurology by researchers at the Cleveland Clinic analyzed data from more than 10 million women across 68 health care systems. The study found that long-term Depo-Provera users, especially those who started after age 31 or used the drug for more than four years, faced a relative risk of intracranial meningioma of 2.43 compared to non-users. Critically, no other contraceptive studied showed comparable danger. The study estimated one additional meningioma tumor for every 1,100 women exposed. At the scale of tens of millions of prescriptions over decades, the public health impact is significant.

September 30, 2025 — Preemption Hearing Before Judge Rodgers

Pfizer’s most consequential pretrial motion argued federal preemption: that FDA regulation of Depo-Provera’s label shields the company from state-law failure-to-warn claims. Pfizer contended it had submitted a formal label change application to the FDA in 2024, which the agency initially denied. The company argued that this rejection proved federal law prevented it from acting.

Plaintiffs countered that Pfizer sat on evidence linking Depo-Provera to meningioma for decades and could have updated the label unilaterally under FDA’s Changes Being Effected (CBE) process long before the 2024 submission. Both sides presented 75-minute arguments. Judge Rodgers did not rule from the bench. Plaintiffs’ lawyers described leaving the courtroom encouraged.

December 2025 — FDA Finally Approves U.S. Meningioma Warning

In December 2025, the FDA formally approved a new meningioma warning on Depo-Provera’s U.S. label. The new language states: “Cases of meningiomas have been reported following repeated administration of medroxyprogesterone acetate, primarily with long-term use. Monitor patients on Depo-Provera CI for signs and symptoms of meningioma. Discontinue Depo-Provera CI if a meningioma is diagnosed.” Pfizer requested the label change itself, partly to cap future liability. The December 2025 warning is the first meningioma disclosure ever included on the U.S. label — over 30 years after FDA approval as a contraceptive.

The label change significantly weakened Pfizer’s preemption argument. Judge Rodgers ordered supplemental briefing to address its implications. A drug company cannot credibly argue the FDA blocked it from warning about a risk that the FDA then approved adding to the label at the company’s own request.

January 2026 — MDL Has 1,775 Cases; Preemption Decision Pending

As of January 2026, the MDL held 1,752 pending cases and 1,775 total filings. State court litigation continued growing in parallel, particularly in New York and Delaware. Judge Rodgers issued Pretrial Order No. 30, confirming that her rulings on preemption and general causation would apply across the entire MDL — not just pilot cases. The stakes of the upcoming decisions were clear to all parties.

March to May 2026 — Case Surge, Now Over 5,500 Federal Claims

New lawsuit filings accelerated sharply. By March 2026, the MDL held 3,099 cases — a nearly 50% increase in one month. By April 5, the count reached 3,490. By May 14, the number climbed to 5,549 federal cases, with state court parallel dockets growing in Delaware (340 cases), New York (119), and California (91). New suits continue to be filed at a rate of several hundred per month. Plaintiffs’ attorneys report holding thousands more unfiled claims pending the outcome of the June causation hearing.

April 22, 2026 — Pfizer Files Motion to Exclude Expert Testimony

Pfizer filed a Daubert motion asking Judge Rodgers to exclude four specific categories of plaintiffs’ expert opinions before any cases go to trial. Pfizer argues that: the drug cannot create brand-new tumors from scratch; less than one year of use cannot cause meningioma; the risk does not persist more than two years after stopping the drug; and the drug does not increase the risk of spinal or malignant tumors.

Critically, Pfizer concedes that current, prolonged use can cause pre-existing benign meningiomas to grow large enough to become diagnosable. That concession is significant. The company is not arguing the drug is entirely safe. It is arguing about the outer boundaries of the risk. Plaintiffs counter that the biological mechanism for tumor promotion also supports initiation — and that the absence of studies on short-term use does not mean short-term use is safe. Daubert hearings are scheduled for June 24 to 26, 2026.

May 14, 2026 — General Causation Discovery Complete

Both sides completed depositions of their general causation experts in May 2026. Plaintiffs deposed Pfizer’s five experts; Pfizer deposed plaintiffs’ five experts. Each side has filed opposing Daubert briefs arguing that the other’s experts should be excluded. Briefing deadlines ran through late May. The June 24 to 26 hearing will determine which scientific opinions reach juries — and whether thousands of cases can proceed to trial.

What the Lawsuits Allege

The lawsuits allege product liability under a failure-to-warn theory. Pfizer had a legal duty, as the holder of the Depo-Provera New Drug Application since 2002, to disclose all known or knowable risks associated with the drug. The FDA’s regulations require manufacturers to update warning labels when new safety information emerges. Plaintiffs argue that decades of scientific literature — from 1983 onward — provided that information. Pfizer chose not to act on it in the United States, even as European and Canadian regulators required warnings that Pfizer added to labels in those markets.

The lawsuits also raise a design defect angle. Pfizer manufactures a lower-dose version of the same drug: Depo-SubQ Provera 104, which uses 104 milligrams of medroxyprogesterone acetate administered subcutaneously, compared to the 150-milligram intramuscular dose of standard Depo-Provera. If a lower-dose formulation achieves the same contraceptive effect with less hormone exposure, plaintiffs will argue that Pfizer had a safer alternative and chose not to promote it. That choice, they allege, placed women at unnecessary risk.

The 150-milligram dose is not incidental. Once injected, medroxyprogesterone acetate sustains elevated levels in the bloodstream for months. Plaintiffs’ attorneys describe it as “setting a hormonal thermostat to high and then sealing the control panel shut for three months.” Meningiomas express progesterone receptors and can grow in response to progestin exposure. Whether Pfizer kept the 150-milligram dose out of clinical necessity or commercial convenience is a question the litigation will press.

The Science: What Studies Show

The biological case for a link between Depo-Provera and meningioma has strengthened considerably since 2024. These are the studies driving the litigation:

What Is a Meningioma?

Meningiomas are tumors that develop in the protective membranes surrounding the brain and spinal cord. They are the most common type of primary brain tumor, accounting for approximately 40% of all reported brain tumors. Most are benign, meaning non-cancerous, but even benign meningiomas can cause severe and permanent neurological damage depending on their size and location.

Meningiomas are classified in three grades. Grade I tumors are fully benign and slow-growing, representing about 80% of cases. Grade II tumors are atypical and grow faster, increasing recurrence risk and often requiring both surgery and radiation. Grade III tumors are malignant and aggressive, representing fewer than 2% of cases but carrying the most serious prognosis. Notably, plaintiffs’ attorneys report that over 25% of the cases they have received so far involve Grade II meningiomas, meaning the severity distribution skews higher than population averages suggest.

Treatment typically involves a craniotomy, a highly invasive brain surgery in which a portion of the skull is removed to access the tumor. Complete removal is not always possible, particularly when tumors develop at the skull base — the location most commonly associated with progestin-linked meningiomas. Incomplete removal may require follow-up radiation or chemotherapy. Patients frequently experience post-surgical seizures, anxiety, depression, and permanent cognitive changes.

Who Qualifies to File a Depo-Provera Lawsuit

Women who received at least two Depo-Provera injections and were later diagnosed with an intracranial meningioma may be eligible to file a lawsuit. The strongest cases involve women who used the drug for five or more years. However, shorter-term use may also support a claim, particularly where the tumor required surgery, caused significant symptoms, or resulted in permanent neurological harm.

Eligible products include branded Depo-Provera, Depo-SubQ Provera 104, and authorized generic versions of medroxyprogesterone acetate injectable, all of which have been included in the MDL. Women must provide documentation of both Depo-Provera use — through medical records, pharmacy records, insurance billing, or provider documentation — and a meningioma diagnosis, confirmed by imaging or pathology reports.

The MDL court has made proof of use a formal requirement. Under Pretrial Order No. 22, all plaintiffs must complete a Proof of Use and Injury Questionnaire and submit supporting records through the BrownGreer MDL Centrality system. The court has authorized subpoenas to pharmacies, clinics, hospitals, and insurers where records are incomplete.

Defendants Named in the Lawsuits

The primary defendant is Pfizer Inc., which has held the New Drug Application for Depo-Provera since acquiring Pharmacia & Upjohn in 2002 and is responsible for the drug’s labeling and safety communications. Additional defendants include Viatris Inc., formed from the merger of Upjohn and Mylan in 2020; Greenstone LLC, a Pfizer subsidiary that distributed authorized generic versions; Prasco Labs, which became the exclusive authorized generic distributor after an FTC-mandated divestiture of Greenstone in November 2020; and Pharmacia & Upjohn, the original NDA holder.

Projected Settlement Amounts

No global settlement has been reached as of May 2026. Settlement discussions typically intensify after bellwether trial verdicts give both sides a clearer sense of jury values. Those bellwether trials are targeted for December 2026, contingent on the outcome of the June Daubert hearing.

Based on comparable pharmaceutical mass tort litigation and the severity of the injuries involved, attorneys tracking the case project settlement ranges in tiers by injury severity:

These estimates are speculative at this stage. They assume plaintiffs prevail on causation at the Daubert hearing and that Pfizer’s preemption defense fails. The defendant is Pfizer, a company with a market capitalization exceeding $150 billion and the financial capacity to fund a global settlement without threatening its business. That financial depth distinguishes this litigation from mass torts where defendant solvency constrains recovery.

Pfizer’s Defense

Pfizer maintains that Depo-Provera is safe and effective. The company’s defenses fall into several categories. On preemption, Pfizer argues that federal FDA oversight of drug labeling preempts state-law failure-to-warn claims, particularly because the FDA initially rejected a label change application in 2024. The FDA’s subsequent December 2025 approval of a meningioma warning substantially undercuts this argument.

On causation, Pfizer concedes that current, prolonged use can cause pre-existing benign meningiomas to grow to the point of diagnosis. The company disputes that the drug initiates tumors from scratch in healthy tissue, and contests the evidence on short-term use and long-term risk persistence after discontinuation. These disputes will be fought at the June 2026 Daubert hearing.

Pfizer also disputes the dosing allegations. The company argues that the 150-milligram intramuscular formulation was clinically appropriate and that the existence of a lower-dose alternative does not make the standard formulation defective.

Statute of Limitations and Filing Deadlines

Women concerned about filing deadlines have more time than they may realize. Two legal doctrines protect most claimants. The discovery rule delays the start of the statute of limitations until a plaintiff knows, or reasonably should know, about both the injury and its possible connection to the defendant’s conduct. Because the link between Depo-Provera and meningioma only entered broad scientific awareness after the 2024 BMJ study, most women could not reasonably have connected their diagnosis to the drug before that publication.

Equitable tolling provides additional protection. Plaintiffs’ attorneys allege that Pfizer willfully concealed the meningioma risk, distributing labeling and promotional materials that omitted known safety concerns for decades. If proven, fraudulent concealment further extends the window to file. Women who received Depo-Provera injections even ten or more years ago may still have viable claims. Anyone with questions about their specific timeline should consult an attorney without delay, as statutes of limitations vary by state.

What This Lawsuit Teaches Consumers

The Depo-Provera litigation is a case study in delayed accountability. The scientific signals were present in 1983. The biological mechanism was documented in detail by 1991. European regulators required warnings that the FDA did not. A lower-dose alternative was available. None of these facts produced a U.S. warning label until 2025, more than 30 years after FDA approval.

The pattern is familiar. A pharmaceutical company holds a profitable product. Regulatory obligations require label updates only when evidence crosses a threshold the company helps define through its own data submissions. Studies that could trigger warnings go unpublished, unsubmitted, or unchallenged. Women who trusted their doctors, who trusted the label, who trusted the system, received a drug without knowing it could cause them a brain tumor. They could not opt for a lower-dose version they did not know existed. They could not choose a different contraceptive based on a risk no one disclosed.

What matters here is not just accountability for Pfizer. It is the question of what women are owed when they take a drug for years in good faith. The answer, in a functioning legal system, is the truth. No warning label. No clinical disclosure. No regulatory flag — until 2025. The Depo-Provera litigation will test whether that silence carries a financial consequence proportionate to its human cost. For more on how pharmaceutical companies face mass tort accountability, see our coverage of the HexClad PFAS settlement and the Google data practices lawsuit.