What is Embryo Cryopreservation
Embryo freezing, also known as Embryo Cryopreservation, is a laboratory procedure that preserves fertilized embryos for potential future use. During an In-Vitro Fertilization (IVF) and ICSI procedures, the female patient is injected with stimulating hormones to promote egg production. This usually produces more eggs than required. After fertilization, only up to 3 of the best quality embryos are injected back into the female patient's uterus to proceed with the fertility treatment. Our fertility center is required by the law to preserve and store surplus unused embryos using embryo cryopreservation technique, to be used at a later date.
Uses and purpose
While there are several reasons to preserve the patient's embryos, the most common one is to have a fail-safe and backup in case the first fertilization treatment is unsuccessful. Besides that, embryo cryopreservation is recommended for couples who might want a second child after the first one, patients with potential genetic reproductive disorders, couples in which one or both partners need to undergo a fertility-affecting therapy (chemotherapy), and patients who are required to take medicine that affects their fertility.
How is embryo freezing performed
Once liquid materials reach low enough temperature, miniature ice crystals begin to form. These crystals are the basic building blocks that make up ice. While a lump of ice might appear smooth and solid, miniature ice crystals have razor-sharp edges that can shred and destroy cellular material, such as newly fertilized embryos.
To avoid that, surplus embryos are frozen with a technique known as vitrification. It is an ultra-fast freezing technique, that allows to bypass the formation of ice crystals, keeping embryos intact and safe. Vitrification happens at a freezing rate larger than 10.000 degrees Celsius per minute. At freezing this rate, almost none to none damage is done to the embryos.
Vitrified embryos are kept in liquid nitrogen, in temperature of at least -196 degrees Celsius. At this temperature, all biological growth processes, including cellular multiplication, cease to happen. The embryos are then stored frozen in time at the moment of their fertilization until they are needed again.
Embryo thawing and implantation
Our fertility center is required by law to store all frozen embryos indefinitely. According to medical studies, frozen embryos are healthy and viable for around 10 years average after freezing, but several couples exist that managed to conceive after longer periods of time.
Once the patient is ready to conceive again, embryos are retrieved from the liquid nitrogen storage and unthawed. This is usually done in the evening before the procedure, that the embryos would be ready the next day. Unfrozen embryos then are injected directly into female patient's uterus, and the treatment proceeds as planned.