Premenstrual symptoms – including mood changes, back and muscle pain, cramps and bloating – have been linked with chronic inflammation, potentially paving the way for better ways to prevent and treat PMS. Researchers have discovered higher levels of a specific protein related to inflammation was positively associated with more severe PMS symptoms, with the strongest link seen with pain and mood.

Up to 90% of women are affected by at least one PMS symptom before their period. For 15-20% of women, however, symptoms are so severe they stop them going about their day-to-day lives. Yet despite extensive research into the cause of PMS, it is still poorly understood. Research is beginning to indicate chronic inflammation contributes to it, but what role the immune system plays is not known.

A team of US researchers has now carried out the largest and most diverse study into the link between inflammation and PMS to show a strong link between symptoms and C-reactive protein, a protein found in blood plasma, the levels of which rise in response to inflammation.

Publishing their findings in the Journal of Women's Health, the researchers used data on almost 3,000 women, assessing the association between elevated CRP levels and PMS symptoms. Blood samples showed that elevated CRP levels was linked to a 26-41% increased risk of having PMS symptoms, including: mood changes; abdominal, back, joint and muscle pain; increased appetite and bloating and breast tenderness/pain. The higher the levels of CRP, the more severe the symptoms were.

Chronic disease risk

"The significant relationships of these PMS with elevated CRP levels have potential clinical implications for the treatment of these symptoms and possibly for prevention by advising women about the factors (e.g., smoking, overweight, and obesity) that are associated with inflammation, as well as suggesting avenues for future mechanistic and epidemiologic research," they wrote.

"The results also suggest that the factors associated with each premenstrual symptom are complex, suggesting potentially different mechanisms for the etiologies of some symptoms. These results suggest that inflammation may play a mechanistic role in most PMS, although further longitudinal study of these relationships is needed."

In a related article, epidemiologist Elizabeth R. Bertone-Johnson said the findings have implications for assessing risk of other diseases. As inflammation is also related to an increased risk of other chronic diseases, it could also help identify women who are more likely to develop them in the future.

She added: "A better understanding of how immune dysfunction and chronic inflammation contribute to premenstrual symptoms could have important implications for primary prevention and provide new avenues for treatment. As millions of women are adversely affected by PMS on a monthly basis, continued research in this area is essential."