Your Complete Guide to Embryo Thawing

Through embryo thawing, your dreams of having a family can become reality. Here’s how you can prepare for the embryo thawing process.

If you have frozen embryos and are ready to begin your journey to family building, understanding the embryo thawing process can help you prepare for the path ahead. Embryo thawing, also known as devitrification, helps prepare your frozen embryos for implantation.

We’re here to provide you with everything you need to know about what embryo thawing is and the factors that can affect embryo survival rates.

If you have frozen embryos and are wanting to begin your journey to parenthood through surrogacy, contact us online now to connect with a specialist.

What is Embryo Thawing?

Embryo thawing is the process of warming frozen embryos to prepare them for implantation. This step in assisted reproductive technology involves carefully reversing the freezing process to ensure the embryos are ready for transfer into the uterus.

The Embryo Thawing Process

The frozen embryos are first removed from storage and identified.


The embryos are gradually warmed to avoid thermal shock. This is done by bringing them to room temperature.


As the embryos warm up, they are rehydrated to replace the cryoprotectant (a substance used to protect biological tissue from freezing damage) with water.


Once thawed, the embryos are assessed for viability. This involves checking for any damage or degeneration.

How Long Does it Take to Thaw an Embryo?

The embryo thawing process is relatively quick, typically taking about 1-2 hours from start to finish. Although some may say it takes 15 minutes, this is the total time required for warming, rehydration and assessment.

Factors Affecting Embryo Survival Rate

Embryo thawing can impact the survival rate, but advances in technology have significantly improved outcomes. Factors that can affect the survival rate include:

  • Freezing Method: Embryos frozen using vitrification (a rapid freezing technique) tend to have higher survival rates compared to those frozen using slow freezing methods.

  • Embryo Quality: The quality of the embryo at the time of freezing can influence its ability to survive the thawing process.

  • Thawing Protocol: Following a standardized and precise thawing protocol ensures the best possible outcome for the embryos.

Modern embryo thawing techniques are highly effective, with survival rates often around 95%. The use of vitrification has particularly improved the chances of embryo viability post-thaw. Proper handling and adherence to protocols are crucial in maintaining high survival rates.

When do They Thaw Embryos for Transfer?

The embryos will be thawed the morning or day of the procedure. Your fertility specialist will only thaw the number of embryos they intend to transfer, and will thaw more if necessary.

Can Embryos be Thawed and Refrozen?

Under certain circumstances, embryos may be thawed and refrozen. This can include embryos at any developmental stage, from zygotes to blastocysts. Embryos that have been previously biopsied and frozen embryos can also be thawed, re-biopsied and frozen for testing.

Understanding the process and factors involved helps ensure the best outcomes for those undergoing fertility treatments. No matter where you’re at in your journey to parenthood, knowing what to expect during the embryo thawing process can help you move forward with confidence.

If you have embryos created or need to connect with a fertility clinic to begin the embryo freezing process, contact us online now to speak with a specialist.