Do aromatase inhibitors and tamoxifen impact the number of oocytes retrieved in oocyte or embryo banking cycles?

Abstract

Research QuestionDoes the number of oocytes retrieved differ in oocyte/embryo banking cycles using tamoxifen versus aromatase inhibitors versus no adjuvant medications? DesignObservational cohort study of patients 18-43 years old undergoing oocyte or embryo banking cycles between 2016 and 2018 recorded in the Society for Assisted Reproductive Technology Clinic Outcome Reporting System. ResultsAutologous fresh banking cycles from 2016-2018 (n=42,854) were analyzed in three different groups: oocyte and embryo banking cycles using aromatase inhibitors (AI, n= 2096), tamoxifen (TAM, n=58), and no adjuvant medication (NAM, n=40,700). The average age at cycle initiation was 35 and the majority of patients were nulligravid (77%) and nulliparous (92%). The number of oocytes retrieved and cryopreserved in all banking cycles was higher in the NAM group compared to the AI group (oocytes retrieved: 14.2 vs 12.6, p<.05, oocytes cryopreserved: 11.4 vs 10.3, p<.05); however, no difference in oocyte yield was observed between the AI and NAM groups in gonadotoxic treatment cycles. There was no significant difference in the number of oocytes retrieved or cryopreserved between the TAM and NAM group in all banking cycles. In the generalized linear model, the adjusted mean difference of oocytes retrieved was significantly less in the AI vs NAM group (-1.25, 95% CI: -1.7, -0.80), p <.05) in all oocyte and embryo banking cycles combined. ConclusionBanking cycles utilizing AI may compromise oocyte yield when used for non-gonadotoxic indications. Our data supports the continued use of AI for gonadotoxic treatment cycles as IVF cycle outcomes and live birth rates are comparable to those for cycles with NAM.