As we all know, a woman’s body goes through many, many changes throughout the course of a menstrual cycle. Those fluctuating hormone levels have a knock-on effect on almost every part of daily life, from mood swings and sleeping patterns to appetite and bloating. But they can also impact how you smell. And how you smell. Confused? So were we. Read on.

It’s a fact that there are more neurons in the female olfactory bulbs than there are in the male, which is basically a fancy way of saying that women have a more sensitive sense of smell. (Yes! So that’s why his feet smell so much worse to you than they do to him.)

Added to that is the well-documented phenomenon of women experiencing a heightened sense of smell during the first few weeks of pregnancy.

But did you know that it happens every month, too? A 2019 study, published in the US scientific journal Hormones and Behavior, compared the smell sensitivity of women during different phases of the menstrual cycle. It found that participants were more sensitive to certain smells such as musk, and the male pheromones androstenone and androsterone, around their fertility window.

So far so makes sense – you’re looking for someone to father your children, you need to be able to sniff him out. But it’s not only how our noses respond to other people’s smells, it’s also about how we smell to other people.

More scientists, this time in Prague, tested a group of women for their body odour throughout their menstrual cycles, and concluded that their armpits smelled the most strongly during their periods. This more intense (and somewhat repellent) odour is thought to have been a signal to primeval man that she is not ready for pregnancy. So go away.

Modern man needs to work harder to get the message, because most of us try to avoid unleashing our natural aromas on the unsuspecting public. If you want to contain body odour during your period – and we’re just guessing you do – the best way is simply up the hygiene stakes, and use plenty of deodorant.