The effects of letrozole+GnRH antagonist versus mere GNRH antagonist during IVF in patients with poor ovarian response

Abstract

Background: poor ovarian response (POR) is inadequate response of ovaries to ovarian stimulation. Different types of therapies have been used in women with POR. Antagonists of gonadotropin releasing hormone (GnRH) have been indicated beneficial results. Letrozole as an aromatase inhibitor reduces the conversion of androstenedione and testosterone to estrone and estradiol. Here we aimed to evaluate and compare therapeutic effects of letrozole+ GnRH antagonist during in vitro fertilization (IVF) in women with POR. Methods: the current study was a randomized clinical trial performed in 2018 in Beheshti hospital Isfahan, Iran. Patients diagnosed with POR who were candidates for IVF were entered and divided into 2 groups: Intervention received 2.5 mg letrozole daily for 5 days from the third day of menstruation cycle and Placebo received placebo. GnRH antagonists were also administered. Data regarding to number of extracted ovocytes, frequency of pregnancy and IVF failure, levels of gonadotropin, duration of gonadotropinusage, initial endometrial thickness, serum levels of Estradiol and number of transferred embryos were collected and analyzed. Results: The two groups of the study were similar in terms of demographic and clinical data prior to the interventions (P-value >0.05). The comparison of the two groups in terms of response to the treatment manifestations, including total gonadotropin (P=0.49), luteinizing hormone (P=0.21), follicular stimulating hormone (P=0.16), anti-mullerian hormone (P=0.94), estradiol (P=0.85), Right ovary size (P=0.48), left ovary size (P=0.84), endometrial thickness (P=0.17), Oocytes number (P=0.80), and successful pregnancy (P=0.74) revealed insignificant differences. Conclusion: Adding letrozole to GnRH antagonists was not associated with better pregnancy results in women with POR who were candidates for IVF. We suggest more studies on larger populations should be performed.