London: Attention, ladies! Men are more intelligent than you thought -- they can actually tell when a woman is having her period just by listening to her voice, says a new study.

Researchers have carried out the study and found it's not their partner's moody behaviour, but actually her voice which can help a man tell when she is menstruating, the as reported.

For their study, the researchers asked recruited three groups of men to listen to voice recordings of 10 women who counted from one to five at four different points over their menstrual cycle.

All four recordings were played in a random order and then the first group of men was asked to guess which were made while the women were on their period.

The tests, conducted by Nathan Pipitone at Adams State College and Gordon Gallup, from SUNY-Albany, revealed that the men were correct 35 per cent of the time described as a "significant" result, the 'Popular Science' reported.

Pipitone and Gallup said all three groups pinpointed the "period" voices more than any other recordings.

In another experiment, a separate group of men – who were not told the study had anything to do with menstruation -- were asked to pick out the most "unattractive" voice. In 34 per cent of cases, they chose the menstrual recording much more than were predicted by chance.

According to the men taking part in the experiments, they could tell the women were menstruating by four key indicators in the recordings -- mood (bad vs good); quality (harsh vs smooth); pitch (low vs high); and speed (slow vs fast). Some said the menstrual recordings appeared lower in pitch, mood.

Pipitone said: "The men seemed to determine menstrual voices by picking the most unattractive voice. It is hormones that give the women away, by inducing vocal change. Vocal production is closely tied to our biology. For example, cells from the larynx and vagina are very similar and show similar hormone receptors."

(Agencies)