Primary dysmenorrhoea is the most commonly encountered gynecological problem in reproductive-age women. Acupuncture has been suggested as an effective treatment of primary dysmenorrhea that may modulate descending pain modulation systems.
In the present study, we used resting-state functional magnetic resonance imaging to investigate possible changes in descending pain modulation systems after acupuncture treatment in women with primary dysmenorrhea. Thirty-four right-handed adult women with primary dysmenorrhea participated in this randomized, single-blinded, sham-controlled study. Each patient was randomly allocated to an 8-week verum or sham acupuncture intervention on the bilateral Sanyinjiao (SP6).
Resting-state functional magnetic resonance imaging was conducted before, during, and after the intervention to measure the spontaneous activity in brain. After the 8-week intervention, both verum and sham groups reported decreased menstrual pain.
However, the cessation of decreased functional connectivity between periaqueductal gray matter and the regions associated with affective pain modulation and attention-related pain modulation were found in the verum but not in the sham group after the 8-week intervention. More decreased functional connectivity has been found in the region associated with non-specific effects of acupuncture intervention after the early stage of acupuncture intervention. These results indicated that verum acupuncture may intercept the altered functional connectivity in descending pain modulation systems in primary dysmenorrhea.