In the present study, the levels of LPA1, LPA4 and LPA5 in the ectopic endometrium were much higher than in the eutopic endometrium in the adenomyosis group, while the levels of LPA2 and LPA3 in the ectopic endometrium were much lower than in the eutopic endometrium in the adenomyosis group. Here, LPAR1 is linked to adenomyosis.