What is Depo-Provera?
Depo-Provera is an injectable contraceptive manufactured by Pfizer Inc. since 1959. The active ingredient in Depo-Provera is medroxyprogesterone acetate, a synthetic form of the hormone progesterone designed to prevent pregnancy.
While Pfizer continues to market Depo-Provera, research has linked long-term use to serious health risks. Depo-Provera became one of the most widely used injectable contraceptives in the United States, with approximately one quarter of sexually active women using the drug at some point.
Current Case Status
Thousands of claims are pending in federal court against Pfizer, alleging that Depo-Provera causes meningioma brain tumors. Those cases continue to proceed through multidistrict litigation (MDL) in the Northern District of Florida, where several cases have been selected for bellwether trials in 2026.
Pfizer has moved to have the cases dismissed from court, arguing that federal law and the FDA prevented Pfizer from changing its label to warn of the cancer risk. That motion could significantly impact the litigation’s future. The court has asked for supplemental briefing on the preemption issue in light of the FDA’s December 2025 approval of a label change for the drug.
Additionally, hundreds of related lawsuits are pending in state courts Delaware, New York, California, Illinois, and Pennsylvania.
The Legal Theory
Depo-Provera lawsuits are primarily based on product liability, design defect, and failure-to-warn claims. Plaintiffs typically allege:
- Failure to Warn: Pfizer failed to adequately warn users about the meningioma risks associated with prolonged Depo-Provera use, particularly after evidence emerged linking progestogens to brain tumors.
- Defective Design: Depo-Provera contains an unreasonably high dose of medroxyprogesterone acetate that is not necessary for effective contraception, creating unnecessary risk of meningioma.
- Negligence: Pfizer failed to conduct adequate safety testing or ignored evidence of meningioma risks for decades, despite warnings in other countries and mounting scientific evidence.
- Fraud and Misrepresentation: Pfizer falsely marketed Depo-Provera as a safe and effective contraceptive option while concealing the risk of meningioma from patients and healthcare providers.
The Scientific Foundation
The litigation centers on whether long-term use of medroxyprogesterone acetate causes or accelerates the growth of meningiomas. For decades, scientific studies have shown a connection between progesterone and meningioma development. In March 2024, a key study published in the British Medical Journal (“BMJ”) found that women who used Depo-Provera for at least one year had a 5.6-fold increased risk of developing intracranial meningiomas. This study supported the prior findings, raising questions about what Pfizer knew about the risks, and when it knew them.
Key Research Findings
Historical Evidence
- A 1986 study found that meningiomas contain a high number of progestin receptors, suggesting a hormonal connection to tumor development.
- Research showed that antiprogesterone medications can help treat meningiomas, further supporting the hormonal link.
- By 2023, researchers confirmed that spinal meningioma growth is directly linked to progesterone exposure.
The BMJ Study (March 2024)
- Examined over 18,000 women who underwent surgery for intracranial meningiomas
- Found 5.6-fold increased risk with one or more years of Depo-Provera use
- Risk increased with duration of exposure
- Represented the first comprehensive assessment of widely-used progestogens and meningioma risk
Supporting Research (September 2024)
- University of Alabama at Birmingham researcher published U.S.-based data in the journal Cancers
- Confirmed increased cerebral meningioma risk with Depo-Provera use
- Association strengthened with prolonged use
- Validated earlier French research findings in a U.S. population
Additional Evidence (August 2025)
- Study in Expert Opinion on Drug Safety by Frey et al. (the Frey study) found women using Depo-Provera for over one year were 3.5 times more likely to develop meningiomas compared to those taking oral contraceptives
- Further strengthened the dose-response relationship
Key Legal Issues
Federal Preemption: Whether federal pesticide regulation “preempts” state labeling requirements. Pfizer argues the FDA’s 2024 rejection of a proposed label change blocks failure-to-warn claims. Plaintiffs counter that Pfizer’s proposed warning was too vague and that the company ignored evidence for decades.
Causation: Whether plaintiffs can establish that Depo-Provera exposure specifically caused their meningioma diagnoses through medical records, expert testimony, and the March 2024 BMJ study.
Product Design: Whether Pfizer should reasonably have known of the meningioma risks based on decades of scientific literature linking progestogens to brain tumors, and whether the drug’s high hormone dose creates unreasonable danger.
Warning Adequacy: Whether Depo-Provera’s U.S. label provided sufficient warnings about meningioma risk, particularly given that labels in Canada, the UK, and the EU included such warnings years earlier.
Statute of Limitations and Discovery Rule: When the clock starts for filing claims—at diagnosis or when plaintiffs could reasonably connect their tumor to Depo-Provera use. The absence of U.S. label warnings until December 2025 may extend filing deadlines under the discovery rule.
Innovator Liability: Whether Pfizer can be held liable for injuries caused by generic versions of Depo-Provera in states like California and Massachusetts.
Damages: Calculation of compensatory damages for medical costs, pain and suffering, lost wages, permanent neurological damage, and potential punitive damages.
Depo-Provera Timeline
1959 – FDA Approves Depo-Provera for Menstrual Disorders
FDA initially approves medroxyprogesterone acetate (Depo-Provera) for managing menstruation, establishing the drug’s entry into the U.S. pharmaceutical market.
1974 – Contraceptive Approval Granted
FDA approves Depo-Provera as a contraceptive method, expanding its use to millions of women seeking birth control options.
1978 – FDA Reverses Contraceptive Approval
FDA reverses its contraceptive approval due to concerns that Depo-Provera may cause cancer, representing an early regulatory red flag about the drug’s safety profile.
1986 – Study Links Meningiomas to Progestin
Research published showing meningiomas contain high numbers of progestin receptors, establishing scientific foundation for understanding hormone-driven tumor growth.
1992 – Depo-Provera Returns to Market
FDA reapproves Depo-Provera as a contraceptive despite previous cancer concerns, allowing widespread use that would continue for decades.
2004 – Black Box Warning for Bone Density Loss
FDA issues its most serious warning about significant loss of bone mineral density in long-term Depo-Provera users, the first major safety warning since the drug’s reintroduction.
2015 – Canadian Labels Include Meningioma Warning
Health Canada updates Depo-Provera labels to reference meningiomas, providing warnings to Canadian users that U.S. patients would not receive for another decade.
2021 – $2 Million Settlement for Bone Density Claims
Pfizer ordered to pay over $2 million in class action settlement for failing to properly warn Canadian patients about bone mineral density loss risks.
March 27, 2024 – BMJ Study Published
Study in the British Medical Journal finds women using Depo-Provera for at least one year have 5.6-fold increased risk of intracranial meningiomas, triggering wave of litigation.
April 2024 – Pfizer Acknowledges Study Findings
Pfizer publicly acknowledges BMJ study results and states intent to work with regulatory agencies to update labels, but does not immediately change U.S. warnings.
June 2024 – Pfizer Submits Label Change to FDA
Following mounting evidence, Pfizer submits proposed label update to FDA including meningioma warning information.
July 2024 – First Patient Speaks Publicly
Lucy Woodward, a nurse and mother of three, shares her story of developing a golf ball-sized meningioma after Depo-Provera use, raising public awareness.
September 2024 – U.S. Study Confirms Findings
University of Alabama at Birmingham researcher publishes study in Cancers confirming increased cerebral meningioma risk in U.S. population, strengthening evidence beyond French data.
October 2024 – First Lawsuits Filed
First Depo-Provera meningioma lawsuits filed, including case by California woman who received approximately 64 injections between 2005-2021 and developed brain tumor requiring surgery.
December 2024 – FDA Rejects Initial Label Change
FDA rejects Pfizer’s proposed label update, stating the data submitted did not adequately support adding a meningioma warning—a decision Pfizer would later use in preemption arguments.
February 2025 – MDL Formation and Judge Assignment
U.S. Judicial Panel creates MDL in Northern District of Florida under Judge M. Casey Rodgers. Judge immediately selects five pilot cases to proceed through discovery and trial, representing expedited and somewhat unusual approach.
August 24, 2025 – Pfizer Files Summary Judgment Motion
Pfizer files motion for summary judgment based on federal preemption, arguing FDA’s rejection of label change blocks state-law claims—potentially case-ending defense if successful.
August 2025 – New Study Published
Study in Expert Opinion on Drug Safety finds women using Depo-Provera for over one year are 3.5 times more likely to develop meningiomas compared to oral contraceptive users.
November 5, 2025 – Judge Defers Preemption Ruling
Judge Rodgers announces she will not rule on Pfizer’s summary judgment motion until FDA decides on the company’s June 2025 label submission, tying court decision to regulatory action.
December 17, 2025 – FDA Approves Meningioma Warning Label
In major development, FDA approves new Depo-Provera label warning users of potential meningioma risk—undermining Pfizer’s preemption defense and officially acknowledging the danger.
March 2026 – Pilot Discovery Phase Concludes
Pilot case discovery scheduled to conclude, marking transition toward potential trial preparation or settlement negotiations.