Embryo Freezing

Fertility preservation techniques such as embryo freezing give women more options and flexibility when it comes to planning their family.

What is embryo freezing (embryo cryopreservation)?

Approximately 50% of patients have extra embryos following their IVF cycle. These embryos can be saved for future use, providing the opportunity for additional attempts at pregnancy from a single IVF cycle.

Women may consider freezing their embryos for social preferences, or cancer fertility reasons (where a woman freezes embryos prior to receiving radiation or chemotherapy treatments which may damage her eggs).

How does it work?

Vitrification is a method of cryopreservation that allows for the ultra-rapid cooling of embryos, preventing the formation of damaging ice crystals. Vitrified embryos have better post-thaw survival rates and can result in higher pregnancy and live birth rates.

Not all patients will have extra embryos for cryopreservation. Only good quality embryos are frozen as poorer quality embryos do not survive the freezing thaw cycle.

Patients are often able to collect a large number of eggs which results in many viable embryos. Any remaining embryos that are not transferred into the woman’s uterus after a fresh IVF transfer may be frozen or “cryopreserved” in small tubes and kept and stored in the laboratory for future use. Cryopreservation allows the patient to limit the number of embryos transferred “fresh” without discarding the unused embryos that could lead to a future pregnancy.

The embryos can be kept in storage for many years. Patients are often able to achieve several pregnancies from just one egg retrieval procedure. These frozen embryos can be transferred back with minimal preparation of the uterine lining. The correct transfer time is calculated based on the stage the embryo was frozen.

NewLife Fertility Centre has tremendous success with this procedure and currently has the highest success rate in the country for achieving a pregnancy from frozen embryo transfer.

Embryo freezing or cryopreservation allows embryos to be stored by cooling them to a very low temperature (-196oC) and storing them in liquid nitrogen. During the freezing process, the embryos are placed in solutions that gradually remove the water from their cells. This protects them from damaging ice crystal formation during freezing

When thawed, they are placed in a different series of solutions to add water back to the cells. These thawed embryos can then be transferred into the uterus during a frozen embryo transfer (FET) cycle for another attempt at pregnancy, without having to undergo the entire IVF cycle. By this means the cost of treatment will be significantly reduced and without the risks of oocyte retrieval or ovarian hyperstimulation.


  • Fertility preservation
  • Genetic testing (CCS/PGS/PGD): embryos must be stored to await results
  • Storage of surplus embryos from an IVF cycle
  • Delay of embryo transfer for medical or other reasons after a fresh IVF cycle

What are the benefits of a FET cycle over a fresh stimulated cycle?

FET is often a good choice over a fresh stimulated cycle if you have frozen embryos to use. Benefits include:

  • Lower cost
  • Less complex treatment
  • Fewer monitoring appointments
  • No risk of ovarian hyperstimulation syndrome (OHSS)
  • No anesthesia or egg retrieval
  • Significantly reduced medication cost
  • Nearly identical success rates

What kind of fertility medications will I take when doing a FET cycle?

You will need supplemental estrogen and progesterone medications to prepare your uterine lining for the FET. You will also continue these medications after the FET. Estrogen is often given in the form of injections every third day. You may also need progesterone injections or vaginal suppositories every day as instructed after the lining sonogram check. If you are unable to tolerate injectable medications, you can discuss with your physician alternative forms of these medications.

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