Fresh versus frozen single embryo transfer in Chinese women of advanced age undergoing IVF/ICSI: a study protocol for a randomized controlled trial

Abstract

Background: Elective frozen cleavage embryo transfer resulted in significantly higher live birth rate in patients with polycystic ovary syndrome but not in ovulatory women compared with fresh embryo transfer. Further, elective single frozen blastocyst transfer had significantly higher live birth rate in ovulatory women compared with single fresh blastocyst transfer. However, it is unknown whether single frozen cleavage embryo transfer results in higher cumulative live birth rate in women of advanced age undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). The aim of this study is to compare the effectiveness of frozen cleavage embryo transfer with fresh cleavage embryo transfer in Chinese women of advanced age. Methods: This study is a double-blind randomized controlled clinical trial (1:1 treatment ratio of frozen embryo transfer vs. fresh embryo transfer). A total of 840 women of advanced age with normal ovarian reserve undergoing the first cycle of IVF or ICSI will be enrolled and randomized into two parallel groups. Participants in group A will undergo frozen single cleavage embryo transfer, and participants in group B will undergo fresh single cleavage embryo transfer. The primary outcome is the cumulative live birth rate of the trial IVF/ICSI cycle within 12 months after randomization. This study is powered to detect an absolute difference of 8% (23% vs 15%) at the significance level of 0.05 and 80% statistical power based on a two-sided test. Discussion: The results of this study will provide evidence for the efficacy and safety of frozen cleavage embryo transfer compared with fresh cleavage embryo transfer in women of advanced age undergoing IVF/ICSI. Trial registration: Chinese Clinical Trial Registry, ChiCTR2000029330. Registered on 25 Jan 2020. Keywords: Frozen embryo transfer, advanced age, in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), live birth, randomized controlled trial.