A frozen embryo is a human embryo that has been cryopreserved (frozen) at a very low temperature, typically around -196°C (-321°F), through a process called vitrification. These embryos are usually created through in vitro fertilization (IVF) procedures, where eggs are fertilized with sperm outside the body in a laboratory setting.

Once the embryos reach a certain stage of development, they can be frozen for future use. This process allows individuals or couples undergoing fertility treatments to preserve excess embryos for later use if they wish to attempt pregnancy again in the future, or if they want to donate the embryos to others for reproductive purposes or for scientific research.

Frozen embryos are stored in specialized facilities known as cryobanks or fertility clinics, where they are carefully monitored and maintained in a state of suspended animation until they are thawed and transferred into a woman’s uterus during an IVF cycle. Thawing and transferring frozen embryos is a delicate procedure that requires precise timing and handling to maximize the chances of a successful pregnancy.