The study compared two methods, vitrification and slow freezing, for preserving human Day 3 embryos. Vitrification thawed 92% of embryos with 100% cell survival, leading to a 41% pregnancy rate. In comparison, slow freezing thawed 58% of embryos with 51% cell survival, resulting in a 39% pregnancy rate. The research shows that vitrification is more effective than slow freezing for preserving Day 3 embryos, with higher survival and pregnancy rates.