Pfizer knew Depo-Provera caused brain tumors since 1983 — waited 42 years to add a warning

Pfizer Knew Their Birth Control Shot Caused Brain Tumors. For 42 Years, They Said Nothing.

In 1983, Pfizer had studies linking progesterone-based contraceptives to meningioma — brain tumors that grow on the protective membranes surrounding the brain. Depo-Provera, their injectable birth control used by millions of women worldwide, was at the center of that research. Pfizer buried the studies. For 42 years.

The Numbers

Women who use Depo-Provera for more than one year are five times more likely to develop meningioma brain tumors. Not twice as likely. Five times. That's not a marginal risk increase — it's a dramatically elevated chance of developing a tumor in your brain from a birth control injection.

42 Years of Silence

Pfizer had the data in 1983. They didn't add a warning to Depo-Provera until December 2025. Between those dates, millions of women received the injection without being told about the brain tumor risk. European regulators forced a warning before the FDA did — American women were the last to know.

3,099 Lawsuits

As of 2026, 3,099 lawsuits have been filed against Pfizer over Depo-Provera and brain tumors. The first trial is scheduled for December 2026. Each lawsuit represents a woman who developed a brain tumor after using a product whose manufacturer knew about the risk and chose not to disclose it.

The Pattern

This is the same company that paid $2.3 billion in the largest healthcare fraud settlement in history (2009). The same company scrutinized during COVID vaccine rollouts. The pattern is consistent: know the risk, suppress the data, profit from the silence, settle when caught.