Swedish study: Some hormonal contraceptives may be more likely to cause breast cancer than others
Scientists from Uppsala University analyzed data from over two million women to determine how different forms of hormonal contraception affect breast cancer risk. The results show that not all contraceptives work the same—some increase the risk more than others. The researchers paid particular attention to contraceptives containing desogestrel, which were associated with the highest increase in risk.
The study, published in JAMA Oncology, is one of the largest studies on the safety of hormonal contraception. A team led by Prof. Åsa Johansson from Uppsala University and SciLifeLab analyzed data from 2006 to 2019 covering more than two million women and adolescents aged 13–49 . Thanks to Swedish national registries, researchers had access to information on both prescriptions and cancer diagnoses.
Not all hormonal contraceptives have the same effect on the risk of breast cancer , says Professor Johansson.
It was the differences in the composition and type of hormones that turned out to be crucial.
The analysis found that desogestrel-containing contraceptives were associated with the largest increase in breast cancer risk —up to 50% with long-term use (five to 10 years). In comparison, levonorgestrel- containing contraceptives, such as intrauterine devices, increased the risk by less than 20%.
“Our results indicate that some progestogens – particularly desogestrel – are associated with an increased risk of breast cancer, while others, such as depot medroxyprogesterone acetate injections, have not been shown to increase the risk ,” Johansson emphasizes.
Interestingly, drospirenone and estrogen pills – also popular in Poland – were not associated with an increased risk of cancer, which may make them a safer alternative for women at risk.
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Regardless of the type of contraceptive, hormonal contraceptive use alone was associated with a 24% increased risk of breast cancer , which translates to one additional case per 7,800 women per year . This risk increased with duration of use, but the study authors emphasize that it is relatively small on a population scale .
Hormonal contraceptives are very effective and bring significant health benefits , so we do not encourage women to stop using them, notes Fatemeh Hadizadeh , co-author of the study.
Experts remind us that hormonal contraception also has many benefits : it protects against unwanted pregnancy, reduces the risk of ovarian and endometrial cancer, and alleviates menstrual cramps and dermatological problems. Nevertheless, when choosing a contraceptive method, it's important to consider individual risk factors, such as age, family history of cancer, and the duration of planned use.
Breast cancer is the most common cancer in women, and until better prevention methods become available, avoiding medications that increase risk could be important – especially for women who are already at higher risk, the study authors conclude.
The new results are not intended to cause fear, but to help women and doctors make more informed choices about contraception, tailored to the health and needs of each patient.
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