Sportswomen make fewer mistakes and have quicker reactions when they are on their period, a study suggests.

Tests designed to mimic the mental processes involved in team sports assessed 241 women’s reaction time, attention, accuracy, and spatial cognition – 14 days apart.

They felt worse when menstruating and thought their performance would suffer – but on average, they were 12% faster at ball-moving tasks and 25% more likely to pass a test of their anticipation skills.

It could explain why women playing contact sports appear injury prone in their luteal phase, between ovulation and menstruation, University College London researchers say.

Lead author Dr Flamina Ronca said the study, conducted with the Institute of Sport, Exercise & Health and published in the journal Neuropsychologia, was “proof of principle” this was linked with fluctuating hormones during the menstrual cycle.

“What we’re seeing is that the the reaction times are a bit slower in the luteal phase and that fits with the fact that we’re seeing a greater incidence of of injuries,” she said.

During the luteal phase, women experience:

• a drop in oestrogen, which stimulates parts of the brain.
• increased levels of progesterone, which inhibits cognitive function and can slow reaction times

These changes begin to reverse during menstruation.

“We wondered if injuries could be a result of a change in athletes’ timing of movements throughout the cycle,” Dr Ronca told BBC News.

And she hoped the study would mean women playing contact sports could adapt their game plan around their menstrual cycle.

“If I know I might be more likely to to make a mistake in timing and movement, I might not go for a tackle that day,” Dr Ronca said.

“I might adopt a different strategy in the game.

“It’s just changing the way we play and being aware.”

“Having this awareness and knowing what’s happening with your body, it’s actually quite comforting to athletes, because at least you have an explanation to why you might be making more mistakes or something might not be quite right.

“And if you know what’s happening, then you can be more more conscious of the decisions that you’re making.”