RESUMO
BACKGROUND: Fundamental and genetic differences between women in the endometrium may cause some to develop endometriosis, whereas others do not. Oral contraceptives (OC) may have an effect on the endometrium, rendering the development of endometriosis less likely. STUDY DESIGN: Endometrium from women using OC (OCE) and menstrual endometrium (ME) from normal cycling women were transplanted onto the chicken chorioallantoic membrane (CAM), and endometriosis-like lesion formation was evaluated. Microarray gene expression profiling was performed to identify differentially expressed genes in the endometrium from these groups. Microarray data were validated by real-time PCR. RESULTS: Less endometriosis-like lesions were formed after transplantation of OCE than after transplantation of ME (p<.05). Most of the differentially expressed genes belong to the TGFbeta superfamily. Real-time PCR validation revealed that inhibin betaA (INHBA) expression was significantly decreased in OCE as compared to ME. CONCLUSION: OC use affects the characteristics of endometrium, rendering it less potent to develop into endometriosis.