In the present study, abnormal expression of spexin (SPX), cannabinoid receptor 2 (CNR2) and POU class 4 homeobox (POU4F3) may have been involved in sensory perception of pain in the myometrium of women with and without adenomyosis, relevant to dysmenorrhoea (FIGURE 5A). This evidence concerns the gene POU4F3 and adenomyosis.