Taking the pill makes women less able to read emotions in other people, according to new research.

The study found that the oral contraceptive may be blurring social judgement when it comes to discerning more subtle facial expressions.

Ninety-five women were challenged to look at black and white photographs of the eye region and select the best of four possible emotional labels that described the expression as quickly as possible.

Previous research has indicated that women on the pill are equally able to recognise more obvious expressions such as happiness or fear compared to those not on the contraceptive.

However, the new study, published in the Frontiers in Neuroscience, is significant because it is the first to study the ability to recognise more complex emotions such as pride and contempt in such detail.

It found that, on average, women on the daily pill were 10 per cent less good at making these judgments.

Dr Alexander Lischke, who led the study at the University of Greifswald in German, said: “Cyclic variations of estrogen and progesterone levels are known to affect women's emotion recognition, and influence activity and connections in associated brain regions.

“Since oral contraceptives work by suppressing estrogen and progesterone levels, it makes sense that oral contraceptives also affect women's emotion recognition.