The potential of letrozole use for priming in vitro maturation ­cycles

Objective: To compare the pregnancy rates with two different methods of priming for in vitro maturation cycles (IVM). Cycles using letrozole together with hCG were compared to cycles using FSH together with hCG in 75 cycles in patients being treated for infertility by IVM. Study design: Retrospective cohort non-inferiority trial Results: Using letrozole for priming was found to not be inferior to using FSH for priming cycles. The live birth rate per transfer was 31.6% in letrozole primed cycles compared to 20.8% in FSH primed cycles (not significant). However, FSH priming produced more oocytes that were mature on the day of retrieval (p = 0.004) and also resulted in more high quality embryos than did letrozole priming (p = 0.004). Conclusion: Letrozole may be used for priming in IVM cycles in which the clinician views the characteristics of letrozole as more desirable than FSH.