There is low-quality evidence that women with endometriosis may require a higher dose of gonadotrophins as they have a lower response to gonadotropins during ovarian stimulation, with one study including 40 women with ovarian endometriosis, and 80 women with tubal infertility undergoing IVF treatment showing a lower ovarian response and significantly higher dose of urinary FSH used, although there was no difference in live birth rates between groups [55,58]. This evidence concerns the gene BRD2 and ovarian endometriosis.