Embryo vitrification | Reproclinic | Assisted reproduction blog
Embryo vitrification

Embryo vitrification: applications and benefits

Embryo vitrification is an assisted reproduction technique that allows embryos to be conserved in optimal conditions for later use. The embryos are obtained from an in vitro fertilization cycle. The method currently used to freeze and preserve embryos is called “vitrification”.Vitrification is an ultrafast freezing technique that uses substances called “cryoprotectants”. These protect the cells, preventing crystals from forming inside them, which would damage their internal structures and cause the cells to die.


What is an embryo?


We know an embryo is the initial stage of development of a living being. In humans, the term is used until the eighth week after conception. Thereafter it is called a fetus.


Everything begins with the union of the spermatozoon (male gamete) and the ovule (female gamete). When they unite, they form a new cell with a nucleus and 46 chromosomes. This union is known as a zygote. The embryo is created when the first cell division of that gamete junction occurs.


On the fifth day of gestation, the embryo is called a blastocyst. The embryo acquires a certain shape, and on the seventh or eighth day, it is implanted naturally.


Today the earliest embryos and those in the blastocyst stage can be vitrified in the laboratory for later implantation.


Uses of embryo vitrification


Currently, the process of vitrification is used to cryopreserve embryos and ovules. It is a very common technique in assisted reproduction.

The vitrification of embryos allows to preserve them intact for a later use. The embryos remain in nitrogen tanks until the woman or couple decides to use them. They can remain indefinitely. In fact, the oldest embryo was 25 years old.


In a cycle of In Vitro Fertilization several ovules are fertilized to select and implant in the maternal uterus the best embryo. Nowadays, many couples decide to keep the embryos not implanted for later use, in the same cycle or to donate them.


Differences with other methods


Embryo cryopreservation has been progressing at an accelerated pace in recent years. Unlike traditional freezing, embryo vitrification cools cells very quickly. Previously, they froze slowly at a rate of approximately 0.3°C per minute, to try to prevent the water inside and around the embryo from freezing.


In the vitrification of embryos, the cells are rapidly cooled at a rate of more than 15,000°C per minute, which prevents ice from forming.


Benefits of embryo vitrification


Several benefits are obtained by embryo vitrification. Among the most important we find:


  • Avoid going through the process of ovarian stimulation again, which reduces the amount of medication and reduces costs.
  • A decrease of the patient’s physical and emotional strain
  • Less probabilities of multiple pregnancies.
  • The vitrification does not alter the quality of cryopreserved embryos.
  • By exponentially improving the number of viable embryos, we can have very high pregnancy rates.
  • Embryos can be vitrified indefinitely without losing their quality.


Although there is a risk that the embryo and oocyte will not survive the defrosting process, this risk is very low. Only embryos and oocytes of good quality are vitrified, which have real possibilities of giving rise to a pregnancy. In an assisted reproduction clinic with a good laboratory, embryo and egg devitrification survival rates should be higher than 95% and 90%, respectively.


In Reproclinic we offer you the best advice in this and other methods and techniques of assisted reproduction. Do you have questions? Do not hesitate to contact us and request a free medical consultation.


Published by Dr Maria Arqué

Medical Director at Reproclinic
Specialist in Obstetrics/Gynecology and Reproductive Medicine

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