BDNF and endometriosis: Therefore, we can speculate that the characteristics of the eutopic endometrium play a key role in dysmenorrhoea in endometriosis and that the effect of molecular biological changes in the eutopic endometrium on the genesis of dysmenorrhoea in endometriosis may be larger than that of the ovarian endometriotic lesions, suggesting that BDNF and TrKB may be correlated with dysmenorrhoea in endometriosis.