...Premenstrual syndrome, or PMS, may be an utter myth, according to new research from the University of Toronto. The study found that there was no obvious link between women's negative mood swings and the premenstrual phase of their cycles.
...The university studied 41 research reports that tracked the change in women's moods throughout their periods, both before and during. Their findings showed no evidence that PMS itself even existed....
“There is so much cultural baggage around women’s menstrual cycles, and entire industries built around the idea that women are moody, irrational — even unstable — in the phase leading up to menstruation,” says Dr. Gillian Einstein, director of U of T’s collaborative program in Women’s Health
...People have blamed mood swings on a woman's "time of the month" for years, with women dubbed irrational or emotional by men, friends or even themselves. A Glamour magazine poll found that 58 per cent of women blamed their periods for their emotional outbursts.