The findings are based on the results of a unique experiment by neurobiologist Karina Heller, who performed 75 brain scans to assess the impact of the menstrual cycle and contraceptive use on brain function. It turned out that taking birth control pills altered brain volume and structure. These changes are now being studied in relation to the risks and causes of endometriosis, a chronic disease that affects approximately one in ten women of reproductive age.
Women have been taking oral contraceptives for over half a century, but scientists still can't fully assess the risks. For example, it's known to reduce symptoms of depression and anxiety in some women and increase them in others. The reasons for this aren't clear, so neurobiologist Karina Heller of the University of Minnesota decided to conduct her own experiment, where she served as both a participant and observer. The findings were published on the website Nature.
In the first phase, she underwent 25 brain scans over five weeks to collect data at various stages of her menstrual cycle. A few months later, she started taking birth control and underwent another 25 scans. Finally, she stopped taking the pill and, three months later, underwent the final 25 scans. In addition to brain imaging, Heller underwent blood tests and completed an emotional state questionnaire.
Observations revealed changes in brain volume and connectivity over the course of a typical month and while taking medication. In the latter case, the indicators were reduced, although this does not directly indicate a decline in brain function. Remarkably, the changes quickly reversed after discontinuing the medication, indicating significant brain adaptability.
Regarding hormonal changes, higher estrogen levels have been shown to influence the functionality of certain brain networks. The opposite effect was observed with progesterone. These findings led Heller to compare her data with those of women with endometriosis. Further research should determine whether these hormonal changes may be the cause of this severe, chronic condition.
