Several hypotheses have been proposed to explain the impact of adenomyosis on implantation, including alteration of the zona interstitium, increased uterine peristalsis, altered endometrial–myometrial vascular development, increased prostaglandin levels in the ectopic endometrial epithelium, increased expression of cytochrome cP450 aromatase in ectopic endometrium, lack of expression of adhesion molecules, and reduced expression of implantation factors. Here, CYP19A1 is linked to adenomyosis.