Women experience chronic pain disproportionately due to complex biological interactions involving sex chromosomes, ovarian hormones, and immune cell responses, according to a review published in the journal Science. The publication highlights that research on menopause has historically been underfunded, despite its impact on half the population and nearly 40% of a woman’s life. Functional pain disorders are two times more frequent in women than in men, appearing in the absence of disease or physical damage, seen in conditions such as rheumatoid arthritis where the vast majority of patients are women, alongside fibromyalgia where 90% of patients are female.
How Ovarian Hormones and Sex Chromosomes Drive Chronic Pain
Fluctuating ovarian hormones heavily influence conditions such as endometriosis, irritable bowel syndrome, migraines, and fibromyalgia. Estrogen can modify pain sensitivity and inflammatory responses in the female gut, an effect absent in men who do not experience high circulating levels of the hormone. Genetic instructions encoded in the X and Y chromosomes dictate cellular aging and disease defense independently of hormones, according to Dan Theodorescu of the University of Arizona. The painful pelvic conditions that affect women during their reproductive years also include interstitial cystitis, pain associated with fibroids, and vulvodynia, while later in life a higher prevalence of osteoarthritis and bone loss compromises mobility, provokes fragility, and can accelerate aging in women.
Female pain mechanisms differ from male immune responses
While male pain models often rely on central nervous system immune cells, female pain mechanisms involve T-lymphocytes and adaptive immunity. Historically, medical science incorporated sex as a biological variable only in 2016, leaving women to face the pervasive dismissal that their pain is psychological. TikTok content creator and nurse Jorge Ángel noted that while testosterone activates anti-inflammatory molecules in men, studies show men develop higher pain memory and anticipatory stress over multi-day exposures. When exposed to the same pain stimulus across several consecutive days, women experienced higher levels of suffering on the first day, whereas in subsequent days the situation inverted and men manifested feeling more pain consistently due to developing greater pain memory and anticipatory stress. Women also have more prolactin, a hormone that activates pain receptors, and while they possess higher initial sensitivity, they count on greater long-term resistance possibly due to evolutionary adaptations linked to processes like childbirth and menstruation.
Researchers seek answers for millions of women
Authors of the review warn that the chronic pain suffered by millions of women in the world is still an enormous and unexplored black box, full of unknowns and prejudices, and state that still more answers are urgently needed.
Hormones and chromosomes drive chronic pain in women
Why do women experience certain chronic pain conditions more frequently than men?
Functional pain disorders such as fibromyalgia and irritable bowel syndrome are driven by interactions between fluctuating ovarian hormones like estrogen, adaptive immune responses, and gut microbiomes.
What role do sex chromosomes play outside of hormones?
Researchers from the University of Arizona point out that X and Y chromosomes contain specific genetic instructions that govern cellular aging and immune defense against major diseases independently of sex hormones.
When did biomedical research start including sex as a biological variable?
Biomedical researchers formally incorporated sex as a biological variable in 2016, a shift that has only recently begun to transform the study of sex-specific pain pathways.