Women who feel moody or grouchy before getting their periods shouldn't blame it all on their hormones, say researchers from the University of Toronto. According to a new meta-analysis of PMS studies, the research team concluded that it is not real — that there is no clear link between women's negative moods and the premenstrual phase of their cycles. The time has come, they say, to put the myth aside.


The researchers, a team lead by psychologist Gillian Einstein, took a look at 47 English language studies found on PubMed, PsycINFO, and various article bibliographies. They conducted a critical analysis of the daily mood data presented in these studies, but could not find any clear evidence that premenstrual syndrome exists.

Specifically, here's what they found:

18 studies (38.3%) found no association of mood with any negative emotion phase (MC phase)

18 studies (38.3%) found an association of negative mood in the premenstrual phase — but combined with another MC phase

7 studies (14.9%) found an association of negative mood and the premenstrual phase

The remaining 4 studies (8.5%) showed an association between negative mood and non-premenstrual phases


It's pretty revealing that only 14.9% studies could link a negative emotional phase with the premenstrual phase, and that 8.5% could link negative emotions with other non-premenstrual phases.

Likewise, Einstein's own research on women's hormonal levels could not establish any kind of association. She concluded that, with a few exceptions, neither absolute hormone levels nor menstrual cycle phases were responsible for altering the moods of women.

Speaking through a release, Einstein had this to say: "Before women even get their first period, they have heard about PMS. The notion is so ingrained in our culture that some of these studies are actually biased because women know the study is about PMS." And just as bad, she feels that the "PMS myth" is perpetuating negative concepts that link female reproduction with negative emotions.


It's important to note that the review did not look into the existence of premenstrual dysphoric disorder (PMDD) — a clinical mood disorder associated with the menstrual cycle (one that is characterized by severe physical and behavioural symptoms in the latter half of the menstrual cycle). The study also did not discount the existence of physical symptoms such as bloating and cramping related to the premenstrual phase.

The entire study can be read at Gender Medicine.

Image: CREATISTA/Shutterstock. Inset image via UofT.