July 13, 2026, 11:47 am | Read time: 4 minutes
The pill or hormonal IUDs are a routine part of life for many women. But do the individual contraceptives differ more than previously thought when it comes to associated health risks? A large Danish study suggests that some progestin-containing contraceptives may be linked to an increased risk of certain brain tumors. The good news: The overall risk of illness remains low, and the observed connection disappeared for most contraceptives after discontinuation.
Connection Between Contraception and Meningiomas
Meningiomas are the most common tumors within the skull in adults. They are mostly benign but can cause symptoms and may require surgery or radiation. Women are significantly more affected than men.1 Since many of these tumors have receptors for the hormone progesterone, scientists have long suspected that female sex hormones could play a role in their development.
It was already known that some high-dose progestins (a group of female sex hormones) can increase the risk of meningiomas. However, whether this also applies to progestins contained in hormonal contraceptives had not been sufficiently investigated. This is precisely the question the study’s authors pursued.
Study Design and Methods
For the study, the researchers analyzed the health data of 3,078,410 women aged 15 to 59 who lived in Denmark between January 1, 2000, and December 31, 2024. The study period thus covered 25 years.2
A total of 1,473 women were included, who were diagnosed with a meningioma for the first time. The researchers compared them with ten similar women without meningiomas, totaling 14,717 control subjects. Women with known influencing factors such as hormone replacement therapy or certain pre-existing conditions were excluded.
Using prescription and treatment data, the authors recorded which hormonal contraceptives were used.
Compared were:
- combined birth control pills
- progestin-only pills
- hormonal IUDs with high or low levonorgestrel doses
- medroxyprogesterone injections
Additionally, the researchers considered how long the contraceptives had been used and how much time had passed since the last use.
Special Risk Identified with Contraception via Injection
The connection was most pronounced with medroxyprogesterone injections. Women using this contraceptive method had more than a fourfold increased risk of a meningioma compared to women without hormonal contraception. For women currently using the injections, the risk was almost ten times higher. However, despite this significant relative difference, the overall risk of illness remains rare.
The authors also observed an increased risk with several birth control pills. Affected were contraceptives with the progestins cyproterone, desogestrel, drospirenone, gestodene, and levonorgestrel. For contraceptives with norethisterone or norgestimate, the data did not provide a clear indication of an increased risk, possibly due to low case numbers. For progestin-only pills, a connection was only found for desogestrel, not for norethisterone.
Hormonal IUDs with a high dose of levonorgestrel were also associated with an increased risk. However, this connection only appeared after more than a year of use. For low-dose hormonal IUDs, the authors found no clear indication of an increased risk.
It was also notable that the risk was mainly increased during current use or in the first year after use. About five years after discontinuation, no increased risk could be detected for most of the contraceptives studied. Only for desogestrel in the combination pill was the increased risk still detectable five years after discontinuation. Additional analyses confirmed this result.
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No Panic: Absolute Risk of Illness Remains Low
The study suggests that the risk of meningiomas may not be limited to just a few high-dose progestins. Several progestins contained in hormonal contraceptives could also be associated with an increased risk. According to the authors, these findings are important for both women and prescribing doctors.
At the same time, the data show that the absolute risk of illness remains low overall. Even though the risk was higher compared to women without hormonal contraception, a meningioma was still rare. Particularly among younger women, the likelihood of an additional case of illness due to use was very low. The only exception was medroxyprogesterone injections, where the connection was significantly stronger.
It is also noteworthy that the increased risk was mainly present during current or recent use. After discontinuation, the connection disappeared for most contraceptives within five years. However, the authors explicitly emphasize that women should not discontinue their hormonal contraception on their own. Instead, the benefits and possible risks should be weighed together with the treating physician.
Study Assessment and Possible Limitations
A major advantage of the study is its scope. It is based on the health data of around three million women and covers a period of 25 years. Several additional analyses reached comparable results, thereby strengthening the study’s validity.
Nevertheless, it is an observational study. It can show that there is a connection between certain contraceptives and meningiomas, but it cannot prove that the contraceptives actually caused the tumors. Additionally, some rarely used progestins could not be reliably evaluated due to low case numbers.