Researchers froze mouse embryos using different chemicals to improve the preservation process. By adjusting techniques and timings, they increased the survival rate and development of the embryos. When comparing two phases, the survival rate went from 25% to 59.8% and the advancement rate from 5.2% to 33.5%. The proportion of embryos growing to blastocysts also improved significantly, from 14.5% to 56.7% in 4-cell embryos. Both cryoprotectants tested in 4-cell embryos had similar survival rates, but more embryos developed into blastocysts with propanediol (64.0% vs 41.5%). Successful pregnancies resulted from using these frozen embryos, leading to the birth of healthy infants. These findings support advancing to larger trials in human IVF programs to possibly enhance success rates in fertility treatments.