[Menstruation, inflammation and comorbidities: implications for woman health]

Menstruation is the genital sign of systemic endocrine events. Heterogeneity of perimenstrual symptoms is associated with levels of inflammation, triggered by the fall of estrogens at genital and systemic level. Aim of the review is to concisely analyze the evidence on: 1) genital and systemic endocrine and inflammatory events associated with periods and perimenstrual symptoms; 2) rationale of intervention to reduce their intensity and impact on women's lives. This review of the literature, selected with a clinical perspective, supports the inflammatory basis of the menstrual event, triggered by the estrogens' and progesterone' fall. Moreover, the review analyzes the endocrine and inflammatory basis of perimenstrual pelvic and extrapelvic symptoms such as: menstrual pain, menstrual irregularities, premenstrual syndrome, gastrointestinal symptoms, catamenial headache, depression, perimenstrual myalgia, joint pain, allergies and asthma, heavy menstrual bleeding, associated ironless anemia, brain and behavioral consequences. Inflammation, with increase of cytokines and other markers, is modulated by the degranulation of mast cells at the basal level of the endometrium, in the blood, in all the organs where mast-cell are already activated from local pathologies and within the brain. The shift of inflammation from physiological to a pathologic intensity increases the severity of perimenstrual symptoms. Symptoms persist, moderately attenuated, also during the hormone free interval (HFI) in contraception. The HFI reduction from seven to two days significantly reduces menstrual inflammation and associated symptoms.