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Injectable Contraceptives May Increase the Risk of Developing Brain Tumors

New research reveals that a popular family of drugs used for contraception and menopausal treatment could be linked to certain brain tumors.

By Lily CareyApr 18, 2024 1:00 PM
Contraceptive Injection. Family planning.
(Credit: Anukool Manoton/Shutterstock)


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For people going through menopause or seeking birth control options, medications that help replace and supplement key sex hormones — known as progestogens — are an essential part of treatment.  

However, new research published last month suggests that these types of medications are associated with higher risk of a common type of brain tumor. Now, scientists are urging caution and pursuing further research on progestogens as a form of contraception and gynecological treatment. 

What Are Progestogens?

Progestogens are a family of medications that mimic the effects of progesterone, a sex hormone produced in the ovaries. These medications are used to treat menopausal symptoms and endometriosis, and are one of the most widely-used forms of contraception globally.   

Read More: An Accurate History of Birth Control: How Long Have Humans Used It?

Yet a 2014 study found that progesterone receptors are also found in most meningiomas — a type of tumor, usually benign, that grows from the outer layers of tissue surrounding the brain. Scientists speculate that this may be why women are often at a higher risk of developing meningiomas.  

Experts say more research is needed to establish a firm causal relationship between these drugs and meningiomas. But as their popularity grows, here’s what you need to know about the risks researchers have uncovered so far. 

Injectable Contraceptives May Carry the Highest Risk

Several studies over the past few years have shown a link between progesterone use and increased risk of intracranial meningioma.   

And a new study, published in 2024 in the British Medical Journal, found that three more commonly used progestogen medications could be associated with a higher risk of intracranial meningiomas — the most common form of brain tumor in the United States, representing about 40 percent of all tumors. These tumors are most common among women and people over 60.

Read More: ‘Honeymoon-Phase’ Chemical Partners Deliver a Toxic Drug to Tumors

Notably, the new study was the first of its kind to investigate the risks associated with more widely-used progestogens, particularly those used in contraception.  Study participants who had used medroxyprogesterone acetate — an injectable contraceptive commonly known as Depo-Provera — were at nearly 5.6 times the risk of developing meningioma than those who had never used the treatment.

Two other medications commonly used for hormone therapy and birth control, medrogestone and promegestone, were also found to increase risk of meningioma. 

The study analyzed data from women admitted to French hospitals for intracranial meningioma surgery between 2009 and 2018, collecting data from over 18,000 patients. Each patient was compared with five other control patients who did not have meningioma but were similar in age and area of residence. 

This risk factor represented a very small proportion of the 18,000-plus cases observed in the study. And because the study was purely observational, scientists say they can’t draw any firm conclusions about whether hormones caused this increased risk. 

Progestogen Use in the United States  

Still, the research team noted, this potential associated risk could pose a greater public health issue. As of 2019, about 74 million women worldwide were using injectable contraceptives, the study notes, with usage rates being significantly higher in low income countries.   

What's more, in the U.S., nearly one in four sexually active women report having used Depo-Provera in their lifetime, per a 2023 report by the Center for Disease Control and Prevention.  

The Depo-Provera contraceptive works by injecting a very small amount of progesterone into the body in order to prevent pregnancy, and shots are typically administered every 11 to 13 weeks. However, the study found that the highest risk for meningioma was associated with high doses or chronic use of Depo-Provera and other progestogens. 

This isn’t the first example of high-dose injectable contraceptive use being associated with meningioma risk. A 2023 study observed 25 patients who were treated for meningiomas at the University of Pittsburgh hospital, all of whose tumors were linked to chronic injectable contraceptive use. The mean duration of use among study participants was over 15 years. 

Given the concerning results of recent studies, the 2024 study authors concluded, further research is "urgently needed" for scientists to gain a better foothold on the risks posed by injectable contraceptives.

Read More: The 7 Most Effective Forms of Birth Control, According to Scientists

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