Periods Don't Make Women Irrational, Forgetful or Incapable of Multitasking

Periods do not cause changes to a woman's attention, working memory or cognitive bias. Loic Venance/AFP/Getty Images

Contrary to the popular stereotype, periods have no impact on a woman's ability to make rational decisions, remember things or focus on more than one thing at the same time.

In a behavioural study of 68 women over two menstrual cycles, scientists found no consistent changes to the participant's cognitive abilities that could be attributed to hormonal changes during menstruation.

"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 Brigitte Leeners, who led the research.

The study, published in the journal Frontiers in Behavioral Neuroscience, used a larger sample than in previous research into how menstruation affects a women's cognitive behaviour. It also covered two cycles, meaning the team was able to work out if any observed changes were consistent over time.

Three aspects of cognition were tested—working memory, cognitive bias (the process involving reasoning, evaluating and remembering) and the ability to pay attention to two things at once.

Participants were tested at different points of the menstrual cycle, blood samples were taken to assess levels of estrogen, progesterone and testosterone and the women were given cognitive tests to complete.

Their findings showed "significant effects" in cognitive bias and divided attention during the first cycle, suggesting changes were taking place as a result of the menstrual cycle, but these changes were not seen again during the second cycle. Overall, there were no differences in performances at different stages of the participants' cycles.

"The hormonal changes related to the menstrual cycle do not show any association with cognitive performance," 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."

The study is not without its limitations and researchers admit that far larger samples will be needed to confirm their findings. The study was also purely behavioral and although previous research has shown there are physical changes to the brain during the menstrual cycle, it does not address this.

"Due to methodological limitations, positive findings in the published literature must be interpreted with reservation," the authors' write.

But they say the current findings indicate "there is no consistent association between women's hormone levels, in particular estrogen and progesterone, and attention, working memory and cognitive bias."