A systematic review of comparing the obstetrical and perinatal outcomes between fresh embroyo transfer & elective frozen embroyo ttransfer

Abstract

Background: Transfer of good quality embroys of elective frozen embroyo transfer (eFET) in subsequesnt cycles is increased because of the introduction of the GnRH agonist trigger protocol and improvements in cryo-techniques. The ongoing discussion focuses on whether eFET should be offered to the overall IVF population or only to specific subsets of patients. Until recently, the clinical usage of eFET was supported by only a few randomized controlled trials (RCT) and meta-analyses, suggesting that the eFET not only reduced ovarian hyperstimulation syndrome (OHSS), but also improved reproductive outcomes. However, the evidence is not unequivocal, and recent RCTs challenge the use of eFET for the general IVF population. Objective and Rationale:To do the systematic review and meta-analysis with an aima to evaluate whether Elective frozen Embroy Transfer is better in positive outcomes for reproductive, obstetric and perinatal outcomes compared with fresh embryo transfer in IVF/ICSI cycles. Also to evaluate the effectiveness of Elective frozen Embroy Transfer eFET in comparison to fresh embryo transfer in different subgroups of patients undergoing IVF/ICSI cycles.Methods:A systematic review was conducted, using PubMed / Medline and EMBASE to identify all relevant RCTs published until March 2020. The participants included infertile couples undergoing IVF/ICSI with or without pre-implantation genetic testing for aneuploidy (PGT-A). The primary outcome was the live birth rate (LBR), whereas secondary outcomes were cumulative LBR, implantation rate, miscarriage, ectopic pregnancy, preterm birth, pregnancy-induced hypertension, pre-eclampsia, mean birthweight and congenital anomalies. Subgroup analyses included normal and hyper-responder patients, embryo developmental stage on the day of embryo transfer, freezing method and the route of progesterone administration for luteal phase support in eFET cycles.Outcomes: Eleven studies, including 5379 patients, fulfilling the inclusion criteria were subjected to qualitative and quantitative analysis. A significant increase in LBR was noted with eFET compared with fresh embryo transfer in the overall IVF/ICSI population [risk ratio (RR) = 1.12; 95% CI: 1.01–1.24]. Subgroup analyses indicated higher LBRs by eFET than by fresh embryo transfer in hyper-responders (RR = 1.16; 95% CI: 1.05–1.28) and in PGT-A cycles (RR = 1.55; 95% CI: 1.14–2.10). However, no differences were observed for LBR in normo-responders (RR = 1.03; 95% CI: 0.91–1.17); moreover, the cumulative LBR was not significantly different in the overall population (RR = 1.04; 95% CI: 0.97–1.11). Regarding safety, the risk of moderate/ severe OHSS was significantly lower with eFET than with fresh embryo transfer (RR = 0.42; 95% CI: 0.19–0.96). In contrast, the risk of pre-eclampsia increased with eFET (RR = 1.79; 95% CI: 1.03–3.09). No statistical differences were noted in the remaining secondary outcomes.Implications: Although the use of eFET has steadily increased in recent years, a significant increase in LBR with eFET was solely noted in hyper-responders and in patients undergoing PGT-A. Concerning safety, eFET significantly decreases the risk of moderate and severe OHSS, albeit at the expense of an increased risk of pre-eclampsia.