Fresh Blastocyst Embryo Transfer is Superior to Morula Embryo Transfer in Young Patients Undergoing in Vitro Fertilization

Objective: To determine if blastocyst embryo transfer yields better pregnancy outcomes compared to morula embryo transfer for fresh and frozen cycles and in donor oocyte recipients. Study Design: Retrospective cohort of patients undergoing in vitro fertilization at a single center. Fresh, frozen, and donor egg recipient cycles between January 1, 2008 and December 31, 2012 were studied. Patients were excluded if they were considered poor prognosis and underwent day 3 embryo transfers. Results: In patients under age 35 undergoing fresh IVF cycle, implantation rates (52% v 29%, p<0.01), clinical pregnancy rates (63% v 38%, p=0.001), and live birth rates (54% v 33%, p<0.01) were all higher after blastocyst embryo transfer. No differences were seen in other SART age groups during fresh IVF. For patients undergoing FET and in donor oocyte recipients, no differences in any pregnancy outcome were between blastocyst and morula embryo transfer. Conclusions: Blastocyst embryo transfer was found to improve pregnancy outcomes in young patients undergoing fresh IVF. The data provides the first studies of morula in FET and donor cycles and found no benefit in these populations to blastocyst embryo transfer. Our study confirmed good implantation rates after morula embryo transfer.