Modulation of myofascial pain by the reproductive hormones: A preliminary report

Statement of problem. The predominance of myofascial pain in women in childbearing years suggests that the reproductive hormones may play a role in this pain disorder. Purpose, The potential influence of these hormones on myofascial pain was evaluated. Methods. Pain patterns were compared across three consecutive menstrual cycles in oral contraceptives users (OC group) and nonusers (Non-OC group). Results. Preliminary results showed that within menstrual cycle variability of daily pain was higher than the nonusers group. In addition to their low variation, pain levels of oral contraceptives users remained positive across the hormonal cycle, whereas in nonusers, peaks of pain alternated frequently with pain-free periods. These data suggest that pain levels in oral contraceptives users may be more constant than those of nonusers. Conclusions. This potential hormonal influence on myofascial pain levels among oral contraceptives users may represent one of the various adverse effects induced by oral contraceptives at the trigeminal area in sensitive subjects. Evidence supporting the link between estrogen, nitric oxide, and inflammatory processes is presented.