Up to 80 percent of women experience the mood swings, low energy and other symptoms common to premenstrual syndrome (PMS). Even though PMS affects the majority of women to varying degrees, the underlying mechanisms of it remain poorly understood by scientists, largely because the entire menstrual cycle has not been considered scientifically important to the study of women’s health.
That idea may be about to change with the finding that the severity of PMS symptoms can be a sign of undiagnosed sexually transmitted infections (STIs).
Some STIs, such as chlamydia, are asymptomatic, and some can cause infertility, making them serious medical issues.
The menstrual cycle is directly associated with women’s health and well-being.
Alvergne and her team analyzed data from 865 users of CLUE, a period tracking app that lets users collect data on menstrual flow, emotional well being and behavior. CLUE also provides science-backed information about menstrual health.
Study participants were asked if they had ever been diagnosed with an STI. Those that responded yes were asked when they were diagnosed and if they had received treatment. Their responses were combined with data they entered about menstrual bleeding patterns, experiences of pain and emotional stress, and use of hormonal contraceptives.
The researchers found that undiagnosed STIs such as chlamydia, herpes or human papilloma virus (HPV) doubled women’s risk of PMS-provoked headaches, cramps and sadness towards the end of their cycle. Women with undiagnosed STIs were also at risk for feeling more emotional throughout the month. After diagnosis of an STI, women’s risk of feeling emotional decreased if they received treatment. No association was found between STIs, pain and emotions among hormonal contraceptive users.
“If you know that severe PMS could be an indictor of an underlying STI, you are more likely to listen to your body,” said Alvergne, an associate professor of anthropology at the University of Oxford.
Menstruation is considered an acute inflammatory event, and inflammation takes a physical toll on the body, using energy that could be dedicated to other functions, Alvergne explained. If a woman is experiencing a strong inflammatory reaction as her period approaches, she may not have the energy to produce adequate amounts of serotonin, a neurotransmitter that counters depression. “So she could understandably be more prone to depression than at other times,” said Alvergne.
The researchers want to follow up on the STI study by analyzing the effect of factors such as social status and living environment on menstruation. They would also like to look at the impact of non-sexually transmitted infections on reproductive health. The STI study is published in Evolution, Medicine & Public Health. The PMS review study is published in Trends in Ecology & Evolution.