Peripheral Estrogens in Women with Endometriosis Undergoing IVF

A consistent body of in vitro evidence supports a detrimental effect of endometriosis on ovarian steroidogenesis, in particular the synthesis of estrogens. However, clinical evidence is scanty and methodologically weak. This study aimed at clarifying whether peripheral 17-β-estradiol during IVF are influenced by the presence of endometriosis. Women undergoing IVF were retrospectively reviewed. Cases were women with a diagnosis of endometriosis. Controls were matched to cases in a 1:1 ratio by study period, age, total number of developed follicles on the day of hCG administration, protocol of hyperstimulation, gonadotropin used, and starting dose. The primary outcome was the ratio between serum levels of 17-β-estradiol and the total number of developed follicles. Fifty-three women with endometriosis and 53 controls were selected. The median ratio (interquartile range) between serum 17-β-estradiol and the total number of developed follicles in the two groups was 207 (164-282) and 201 (144-268) pg/ml, respectively (p = 0.46). Sensitivity analyses on the magnitude of the follicular response, the history of surgery for endometriomas, and the presence of endometriomas did not show any subgroup at increased risk of peripheral estrogens impairment. Endometriosis does not influence peripheral levels of 17-β-estradiol during IVF. Our findings argue against a biologically relevant effect of the disease on ovarian estrogen-synthesis.