The contraceptive pill could make it harder for women to read emotions.

A new study has shown that women who take the pill could have more trouble reading a person's emotions from their facial expressions. The most common side effects associated with the oral contraceptive are weight gain, mood swings, and headaches. This is the first time that external emotion deciphering has been examined in relation to the pill. Published in journal Frontiers in Neuroscience and carried out in the University of Greifswald, Germany, the research included data from 95 healthy women. The group were shown a series of black and white photos of the area around people's eyes, including four emotion options below. The woman were asked to pick what emotion best suited the image as quickly as they could. The participants who took the pill (42) were less able to correctly read the facial expressions compared to their counterparts (53) who were not on the pill. Study senior author, Dr Alexander Lischke, said that if the pill caused "dramatic impairments" in women's abilities to recognise emotions, it would have been noted long before now. "We assumed that these impairments would be very subtle, indicating that we had to test women's emotion recognition with a task that was sensitive enough to detect such impairments," he said. "We, thus, used a very challenging emotion recognition task that required the recognition of complex emotional expressions from the eye region of faces. "Whereas the groups were equally good at recognising easy expressions, the oral contraceptive pill users were less likely to correctly identify difficult expressions." He said that further tests were necessary, but that if the pill was affecting emotional recognition users should be given more detailed information about its side effects.