A research team led by Emma Pierson from Stanford University and Microsoft Research New England, US, found that the menstrual cycle had a greater effect on fluctuating mood, behaviours and vital signs compared to daily, weekly and seasonal cycles.
The team’s study, published [February 2] in the journal Nature, is built on a substantial dataset of 241 million observations from 3.3 million women across 109 countries, including Australia and New Zealand.
Pierson stresses that the key finding – that the menstrual cycle is often larger than the daily, weekly, and seasonal cycles – doesn’t mean that women are more volatile than men.
“We make no comparison across genders or sexes; previous research has not found sex differences in volatility, and men have hormone cycles too,” she says. “Rather, it just means that the menstrual cycle is at least as important as the less stigmatised daily, weekly, and seasonal cycles, and we should normalise it and destigmatise talking about and studying it.
“It should be as easy to talk about as the sleep cycle. We should also prioritise collecting data on it – for example in health records and health apps – which is not always done. We should also make sure clinicians consider it when treating patients – which they do not always do.”
