After multiple embryo transfers without success, it’s natural to question why If you’ve transferred high-quality blastocysts — especially chromosomally normal embryos (PGT-A tested) — each one should offer roughly a 50% chance of pregnancy. So when several transfers fail, even with embryos that look normal under the microscope, it may point to a deeper issue: The problem might not be the embryo… it may be the uterus. Dr. Sher uses a simple analogy: The embryo is the seed. The uterus is the soil.