Embryo Freezing

Part I: Fertility Treatment

Prior to making a decision regarding freezing your embryos, you would have undergone a fertility treatment. These treatments are lengthy and arduous procedures and require you to follow a highly structured plan with multiple steps. Following a strict medication schedule for ovulation induction to egg retrieval and fertilization is strenuous and may require multiple cycles before it is successful. After fertilization has been successfully completed and the embryos have been cultured, many women chose to preserve the surplus embryos. You may do this to ensure you have the possibility of having another child, in case the first cycle of pregnancy fails or in the future without having to undergo an expensive and laborious fertility treatment again.

Part 2: Cryopreservation

Embryo freezing or embryo cryopreservation has two main steps: Cooling the embryos to extremely low temperatures (-196℃) using specific lab equipment Preserving the frozen embryos in liquid nitrogen. The embryos are not harmed in this process and their structure and health are maintained. Embryos can be frozen during different stages of development, immediately at the first stage when they are just a single cell, or at the blastocyst phase (after 5-6 days of development into a cluster of cells).

Part 3: Thawing

If in the future you want to use the embryos, they have to be thawed. This works as follows:

The thawing takes place rapidly within 2-3 seconds, wherein the embryos will be warmed to body temperature. The antifreeze from the embryo also have to be removed, which is done by incubating the embryo in decreasing concentrations of the antifreeze, and increasing concentrations of water. This entire process takes around 40 minutes, after which the embryo will be ready to be transferred into your uterus.

Part 4: Embryo Implantation

Before transferring the embryo into your uterus, the doctor has to ensure that your body is able to form an endometrium lining as part of a normal menstrual cycle. If so, you will likely also be prescribed hormonal medication to enhance the endometrium receptivity. In case, you are do not ovulate, hormonal medication will be given to mimic a natural cycle, in order to have your endometrium ready for embryo implantation.

What Should I Expect From This Procedure?

The main goal of the cryopreservation of your embryos is to have them available for use in the near or distant future without undergoing a fertilization treatment again.

The embryos can be stored indefinitely, but this depends largely on the country of treatment and the local regulations. This can range from 10 years to as long as 30 years.

By freezing your embryos you have already chosen the sperm that has fertilized your eggs. This is an important decision, and should be rightly considered.

Research has shown that pregnancy rates are increased after frozen embryo transfers, but the entire process still varies greatly between patients and is greatly influenced by your age. Though embryos survive the thawing process better than eggs, in many cases none of the embryos survive thawing.