Determination of post-transfer pregnancy rates inembrious going to day 6

Selection of blastocysts before embryo transfer strengthens the chances of a healthy implantation. Embryo blastocyst development is monitored on the 5th and 6th day after ICSI. This process will allow the embryo to attach to the uterus and thus increase the chance of pregnancy, which is the primary goal. While high pregnancy and implantation rates are achieved with blastocyst transfer, the rate of multiple pregnancy decreases. Sometimes embryos do not reach the expected cell counts and follow behind. On day 5, the origin may remain in the morula stage or early blastocyst stage. In this case, the embryo is kept until day 6 to complete its development. In this study, day five and day six blastocyst transfer rates determined among cases admitted to Acıbadem Altunizade Hospital IVF Center between 2010 and 2022 were investigated retrospectively. In the study, 2052 cases with blastocyst transfer were evaluated. 1998 cases were identified as day five blastocyst transfer and 54 cases as day six blastocyst transfer. Pregnancy occurred in 1388 (67.6%) of 2052 cases and no pregnancy occurred in 664 (32.4%) cases. As a result of the analysis, the pregnancy rate in day 5 ET cases was statistically significantly higher than day 6 ET cases (p=0.002; p<0.01). Day 5 embryo transfer cases had a significantly higher number of grade II embryos than day 6 (0.002; p<0.01). Since day 5 ET patients had a higher pregnancy rate than day 6 ET patients, it was concluded that the implantation success of day five blastocysts was higher. However, pregnancy-positive cases on day 6 ET showed that transfer can be performed in cases where the number of embryos that can be transferred is low.