Single blastocyst transfer yields significantly highter clinical pregnancy (CP) rates compared with one or more cleavage embryo transfer in patients with a low number of fertilized oocytes( < 4): an analysis of 6,795 first IVF cycles from the SART registry

There has been a trend in IVF cycles to culture to blastocyst (day 5-6) as blastocyst transfer has been shown to have higher clinical pregnancy rates and live birth rates compared to cleavage stage transfer (day 2-3). Practitioners are currently better able to choose a euploid embryo based on blastocyst morphology, and a blastocyst transfer is more physiologic as this is the time when an embryo enters the uterus in a natural cycle. However, there is always the risk that some or all of the embryos will not make it to the blastocyst stage.
Source: Fertility and Sterility - Category: Reproduction Medicine Authors: Tags: Oral Presentation Source Type: research