A Cross-Sectional Analysis of Live Birth Rates in Day 5 Fresh Versus Vitrified Single Blastocyst Transfer Cycles

Abstract

Background: The use of frozen embryo transfers (FETs) in assisted reproduction has increased worldwide. Proponents of FETs suggest that controlled ovarian hyperstimulation (COH) in a fresh transfer impairs endometrial-embryo synchronicity, however there has been conflicting evidence on live birth rate (LBR) and clinical pregnancy rate (CPR) outcomes. Aim: To compare LBRs and CPRs between single autologous day 5 fresh versus vitrified blastocyst transfer cycles, in order to investigate the impact of COH on embryo-endometrium asynchrony. Method: A large cross-sectional analysis of 6,002 embryo transfers (ETs), comprising of 3774 fresh and 2228 FET cycles from 2016-2019. Inclusion criteria: f..