Researchers have found that menstruating from an organ at one end of the body doesn’t affect the ability to think with an organ at the other end. In other words, a woman’s period doesn’t affect her brain’s ability to function like a normal, adult person.

Colour us shocked. (And by ‘shocked,’ we mean the pure sky blue of advertorial menstrual blood, of course.)

Women not being able or fit for fill-in-the-blank because ‘omg le periodz irrationale‘ is still, for many, an acceptable ideology. But Dr, Brigitte Leeners, MD, and a team of researchers, after examining three aspects of cognition across two menstrual cycles, found that the levels of female hormones oestrogen, progesterone and testosterone have no impact on women’s working memory, cognitive bias, or ability to pay attention to two things at once.

While some hormones were associated with cognitive changes across one cycle in some of the participants, these effects didn’t repeat in the following cycle. Overall, none of the period hormones the team studied had any replicable, consistent effect on participants’ cognition.

“As a specialist in reproductive medicine and a psychotherapist, I deal with many women who have the impression that the menstrual cycle influences their well-being and cognitive performance,” said Dr. Leeners. Wondering if this anecdotal evidence could be scientifically proven — and questioning the methodology of many existing studies on the subject — the team set out to shed some light on the mental effects of a period.

The study drew on a much larger sample than previous studies and, (unlike most similar studies) followed women across two consecutive menstrual cycles. The team, working from the Medical School Hannover and University Hospital Zürich, recruited 68 women to undergo detailed monitoring to investigate changes in three selected cognitive processes at different stages in the menstrual cycle. While analysis of the results from the first cycle suggested that cognitive bias and attention were affected, these results weren’t replicated in the second cycle. The team looked for differences in performance between individuals and changes in individuals’ performance over time, and found none.

“The hormonal changes related to the menstrual cycle do not show any association with cognitive performance,” Dr. Leeners said. “Although there might be individual exceptions, women’s cognitive performance is in general not disturbed by hormonal changes occurring with the menstrual cycle.”

Dr. Leeners continued, suggesting that, while this study represents a meaningful step forward, larger samples, bigger subsamples of women with hormone disorders, and further cognitive tests would provide a fuller picture of the way that the menstrual cycle affects the brain. In the meantime, she hopes her team’s work will start the long process of changing minds about menstruation.