SISU Hospital

Embryo, Ovum & Gamete Freezing

Ovum Freezing

Embryo freezing is a procedure that allows people to store embryos for future use. A person can also freeze eggs, which are not fertilized. An embryo forms after fertilization and after the cells start to divide.
The first successful pregnancy resulting from freezing a healthy embryo took place in 1980. The term Embryo means from the moment that cells divide after fertilization until the eight weeks of pregnancy.
Before freezing can take place, First, patients need to create suitable embryos.
First, the person will take hormone injections to produce more eggs. These eggs are retrieved under Transvaginal ultrasound guidance. A person may wish to freeze their eggs if she wants.
The eggs were fertilized by sperm IVF or ICSI technique, in the laboratory. After fertilization, embryos are kept in special culture media for 2 to 6 days in the incubator. Once the embryos reaches the blastocyst stage, the embryo transfer will be done.
The surplus embryos are frozen for future use.
While freezing the biggest challenge is the water within the cells. When this water freezes, water crystals can form and burst the cell. This is the reason for the poor success rate in frozen embryo transfer.
Now, slow freezing is completely replaced by the vitrification method.


In this process, the embryologist vitrifies the cryoprotected Embryos so quickly that the water, molecules do not have time to form, Ice crystals. This helps to protect the embryos and ovum, increases their rate of survival during thawing. After freezing is complete, embryo’s are stored in liquid nitrogen.

Success rate of thawing Frozen Embryo

The process of thawing a vitrified embryo after cryopreservation has a relatively high success rate and good chances of delivering healthy babies, no increase in development anomalies.
Research showed that vitrification increases an embryo’s chances of survival, comparable with fresh transfer.

How long can Embryos and Gametes stay frozen?

In theory, frozen embryos or gametes can remain viable for any length of time.
The embryo’s remain in sealed containers at a temperature of -321’F. At this temperature, no biological process such as aging can occur.
The length of time that a person and the fees can store their embryos will be discussed in person.