Last Updated: March 2026

Depo-Provera Side Effects: What Every Woman Should Know in 2026

Depo-Provera (medroxyprogesterone acetate) is a hormonal birth control injection administered every three months. While it has been used by over 24 million women in the United States since 1992, growing evidence has revealed serious side effects that Pfizer failed to adequately disclose — including a significant link to meningioma brain tumors.

Common Side Effects of Depo-Provera

The following side effects are well-documented and listed on the current Depo-Provera label:

• Irregular menstrual bleeding — spotting, breakthrough bleeding, or missed periods
• Amenorrhea — complete cessation of periods (occurs in ~50% of users after one year)
• Weight gain — average of 5-8 pounds in the first year, with continued gain over time
• Headaches
• Mood changes — depression, anxiety, mood swings
• Decreased libido
• Abdominal pain or discomfort
• Injection site reactions — pain, redness, swelling
• Acne
• Hair loss or thinning
• Nausea
• Breast tenderness

Serious Side Effects of Depo-Provera

• Bone density loss — FDA black box warning since 2004; may not be fully reversible
• Blood clots — deep vein thrombosis (DVT) and pulmonary embolism
• Allergic reactions — severe anaphylaxis in rare cases
• Ectopic pregnancy — if pregnancy occurs while using Depo-Provera
• Liver problems
• Delayed return to fertility — can take 10-18 months after last injection

Meningioma Brain Tumors: The Side Effect Pfizer Didn't Warn About

The most alarming side effect of Depo-Provera was not adequately disclosed for over 30 years: a significantly increased risk of meningioma brain tumors.

What the Research Shows

A 2024 study published in the British Medical Journal (BMJ) analyzed health records and found:

• Women using injectable medroxyprogesterone for 1+ years had a 5.6x increased risk of developing intracranial meningiomas
• The risk was dose-dependent — more injections correlated with higher risk
• The risk was specific to medroxyprogesterone acetate, not other hormonal contraceptives
• Risk remained elevated even after discontinuation

Why Didn't Pfizer Warn Patients?

Meningiomas are known to have progesterone receptors, and the scientific literature has discussed the hormone-tumor connection for decades. Plaintiffs in the current lawsuit (MDL 3140) allege that Pfizer had access to this data and chose not to adequately warn patients or physicians. The FDA did not add a meningioma warning until December 2025 — 33 years after Depo-Provera was approved.

Symptoms of Meningioma

If you used Depo-Provera and experience any of these symptoms, consult a doctor immediately:

• Persistent or worsening headaches
• Vision changes (blurred vision, double vision, vision loss)
• Hearing loss or ringing in ears
• Memory problems or confusion
• Seizures
• Weakness or numbness in limbs
• Speech difficulties
• Balance problems

Learn more about meningioma brain tumors →

Depo-Provera vs. Other Birth Control: Risk Comparison

Not all hormonal contraceptives carry the same meningioma risk. The BMJ study found that the elevated risk was specific to injectable medroxyprogesterone acetate. Oral contraceptives, IUDs, and implants were not associated with the same level of increased risk.

Compare Depo-Provera to generic medroxyprogesterone →

What You Can Do

If you received Depo-Provera injections and were later diagnosed with a meningioma:

1. Document everything — gather medical records, injection history, and imaging results
2. Check your state's deadline — statutes of limitations vary. Find your state's filing deadline
3. Get a free case evaluation — determine if you qualify for compensation