Obesity does not alter endometrial gene expression in women with endometriosis.

Abstract Research Question Does obesity impact on endometrial gene expression in women with endometriosis, specifically women with stage I disease? Design Differential gene expression analyses was performed on endometrium from women with and without endometriosis (n = 169). Women were diagnosed following surgical visualisation and staged according to the revised American Society for Reproductive Medicine (stage I-IV). Women were grouped by body mass index (kg/m2) as underweight, normal, pre-obese or obese. After accounting for menstrual cycle stage, endometrial gene expression was analysed by BMI (continuous and grouped) in women with endometriosis and non-endometriosis controls. Results There was no significant interaction effect between BMI and endometriosis status on endometrial gene expression. We have previously reported that obese women with endometriosis have a reduced incidence of stage I disease, however, stratifying our analysis into stage I endometriosis versus combined II, III and IV endometriosis we failed to reveal any differentially expressed endometrial genes between normal, pre-obese and obese patients. Conclusions Despite obesity having deleterious effects on endometrial gene expression in other gynecological pathologies (e.g. endometrial cancer and PCOS), our results do not support an association between BMI and altered endometrial gene expression in women with or without endometriosis.