If there are any good quality spare embryos left over from your treatment cycle, these can be frozen and stored for future use. They can be used if your treatment is unsuccessful or for a sibling pregnancy.
Embryos are frozen by removing the fluid from inside the cells before freezing them in liquid nitrogen. This is called vitrification. Embryos rapidly frozen in this way have excellent survival rates – over 95% – after being thawed. In recent years, success rates using frozen embryos have really improved. We now see very similar success rates using frozen embryos to our fresh IVF cycles.
Embryos are best frozen either on Day 1 or Day 5 after egg collection. Only top-quality embryos can survive the process.