At Waterstone Clinic, we use a technique known as vitrification to freeze embryos. This involves freezing the embryo about 600 times faster than in conventional slow rate freezing. This ultra-rapid process is so fast that it allows no time for ice crystals to form in the embryo. As a result, vitrification avoids trauma to the embryo.
Slow-rate (conventional) freezing methods had significantly poorer success rates. This was due to 20-30% of embryos not surviving the freeze-thaw process, and those that did survive had less than 50% chance of resulting in a pregnancy than freshly transferred embryos. In contrast, vitrified embryos have a greater than 80% freeze-thaw survival rate, and a pregnancy generating potential that is comparable to fresh embryos.