SERUM AND FOLLICULAR ENDOCRINE PROFILE DIFFERENCES BETWEEN MODIFIED NATURAL CYCLES AND STIMULATED CYCLES

Background. It has been found that higher follicular anti-müllerian hormone (AMH) concentrations predict higher fertilization, implantation and pregnancy rates in women undergoing controlled ovarian hyperstimulation (COH). 1, 2 Higher serum luteinizing hormone (LH) concentration may negatively affect oocyte quality.3 The aim of our study was to compare follicular and serum AMH, LH, follicle-stimulating hormone (FSH), estradiol (E2) and progesterone (P) concentrations in modified natural cycles (MNC) and COH cycles. Methods. Women undergoing in vitro fertilization (IVF) were included; 29 in MNC and 30 in COH cycles with gonadotropin and GnRH antagonist. Serum and follicular fluid samples were obtained on the day of oocyte retrieval. Results. Follicular AMH concentration was 2 times higher in MNC than in COH group, while serum AMH concentrations were comparable in both groups. Serum LH concentration was almost 50 times higher and follicular LH concentration almost 8 times higher in MNC than in COH group. Follicular LH concentration was almost 4 times lower in follicles with consequent implantation than in follicles without implantation. Serum and follicular concentrations of AMH and LH correlated with each other in both cycle groups. In COH group, serum AMH concentration was significantly higher with increasing number of retrieved oocytes and significantly lower with women’s advancing age. In MNC group, there was a negative correlation between follicular AMH concentration and volume of follicular aspirate as well as between serum LH concentration and volume of follicular aspirate. Serum FSH concentration was 2 times higher in MNC than in COH group, while follicular FSH concentrations were comparable in both groups. Serum E2 concentration was in MNC 8 times lower and follicular E2 concentration 2 times higher than in COH group. Serum P concentration was 8 times lower in MNC than in COH group, while follicular P concentrations were comparable in both groups. Conclusions. The results of our study indicate that serum and follicular endocrine profile is different in MNC and in COH cycles. Extremely high follicular and serum LH concentration in MNC might affect endometrial receptivity and thus have negative effect on IVF success. Higher serum AMH concentration can predict higher number of retrieved oocytes in COH group