Undiagnosed sexually transmitted infections (STI) can increase negative premenstrual symptoms (PMS) in women, according to a study.

Despite being known to have an anti-social effect on women’s lives, altering their moods, energy levels, eating habits and even sex drive, periods are not recognised as a scientific factor in the study of female health. However, since some STI infections are asymptomatic, for instance 70 percent of people diagnosed with Chlamydia are unware of it, and can lead to fertility issues, the study authors caution that these results are significant, and that reproductive health needs to be taken more seriously by both the scientific community and women in general.

Lead author Dr Alexandra Alvergne of Oxford University, said: “Even now, when I write a research application on PMS, I still think ‘will this be taken seriously?’ that needs to change. Not understanding or even acknowledging that PMS is more than ‘women’s raging hormones’ but rather, the by-product of cyclical immunity makes it harder to identify diseases and can even delay diagnosis of infections such as STIs, which can affect women’s fertility.”

Dr Alvergne said: “Our research shows that by better understanding their period and menstrual cycle, women could potentially improve their health. If you know that severe PMS could be an indicator of an underlying STI, you are more likely to listen to your body.” The study appears in the journal Trends in Ecology and Evolution.