Does PMS really exist?

By Sarah Moses Wednesday, April 3, 2013 - 15:21
PMS as we know it might be a myth, new research shows. Yes, many women find their mood changes over their monthly cycle. But in reality there’s a huge variety in how and when they are affected.

Little evidence

It’s pretty well accepted that when it comes to ‘that time of month’, a woman is no fun to be around. Premenstrual syndrome – which includes symptoms like being in a bad mood and bloating that a woman gets right before her period – pops up in the media all the time. But now research shows there isn’t good scientific evidence for PMS.

Almost 40 percent of women don’t have any change in mood linked to their monthly cycle, according to the research, which reviewed 47 studies on women’s moods and their periods.

Another 40 percent of women do feel down in the dumps before they get their period but this and other symptoms continue once they begin menstruation. What these women experience might better be described as ‘peri-menstrual syndrome’ (meaning ‘syndrome around the time of your period’) rather than premenstrual syndrome.

Classic PMS

Just three out of twenty women get ‘classic PMS’ – the kind that shows up just before menstruation and goes away when it begins. So the vast majority of women simply don’t experience what we’ve long thought of as PMS.

But even if a woman isn’t more likely to be in a foul mood before her period, many women’s moods do go up and down as their hormone levels change during the month, the study found. When this happens, and how much it happens, really depends on the woman, as well as on many other factors that affect mood, like stress or sleep.

History of PMS

But if there’s not a whole lot of scientific proof for ‘classic PMS’, where does the commonly-held belief come from? A negative mood was first linked to the menstrual cycle in the 1930s and it still gets a lot of play in research to this day.

Part of the problem is that there’s no real definition of PMS, including when exactly it begins, when it ends, and what the symptoms are – whether it’s just a question of being irritable and moody or if physical changes like bloating and cramps are part of PMS too.

Throughout history, a woman’s menstrual cycle has carried a lot of meaning – it’s been feared, thought of as dangerous, and women have been taught to hide it. And research shows that it continues to be seen negatively in many cultures, a message which is spread by the media and through advertising.

Though this study showed that hormones do affect mood and PMS for many women, it’s definitely not that simple. A woman’s cultural background, the society she lives in, her age, and her genes, can all affect changes in her mood over the course of her menstrual cycle.


Girls, do your periods affect your moods? Guys, is your girlfriend hard to be around before her period? Tell us here or on Facebook!

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