Immediate versus postponed frozen embryo transfer after IVF/ICSI: a systematic review and meta-analysis

AbstractBACKGROUNDIn Europe, the number of frozen embryo transfer (FET) cycles is steadily increasing, now accounting for more than 190  000 cycles per year. It is standard clinical practice to postpone FET for at least one menstrual cycle following a failed fresh transfer or after a freeze-all cycle. The purpose of this practice is to minimise the possible residual negative effect of ovarian stimulation on the resumption of a norm al ovulatory cycle and receptivity of the endometrium. Although elective deferral of FET may unnecessarily delay time to pregnancy, immediate FET may be inefficient in a clinical setting, following an increased risk of irregular ovulatory cycles and the presence of functional cysts, increasing the r isk of cycle cancellation.OBJECTIVE AND RATIONALEThis review explores the impact of timing of FET in the first cycle (immediate FET) versus the second or subsequent cycle (postponed FET) following a failed fresh transfer or a freeze-all cycle on live birth rate (LBR). Secondary endpoints were implantation, pregnancy and clinical pregnancy rates (CPR) as well as miscarriage rate (MR).SEARCH METHODSWe searched PubMed (MEDLINE) and EMBASE databases for MeSH and Emtree terms, as well as text words related to timing of FET, up to March 2020, in English language. There were no limitations regarding year of publication or duration of follow-up. Inclusion criteria were subfertile women aged 18-46  years with any indication for treatment with IVF/ICSI. Studie...
Source: Human Reproduction Update - Category: OBGYN Source Type: research