Cryopreservation



Embryo freezing

We have already mentioned that of all the embryos created with IVF only a limited number (3-4) are transferred to the uterus. It is not unusual for more good quality embryos to remain in the laboratory after the transfer. These embryos can be cryopreserved under deep freezing conditions (-196oC) in specially designed areas of the embryology laboratory, for 5 or more years.



Possibilities and chances of pregnancy

The couple may use the cryopreserved embryos for a future pregnancy without the need of repeated ovarian stimulation, egg/ sperm collection and IVF, but only monitoring and embryo transfer.

International pregnancy rates using frozen-thawed embryos are slightly lower than fresh embryos.

This is due to the fact that the best quality embryos have already been selected and transferred at the initial fresh cycle, and also because some of the embryos may be partially or totally destroyed upon thawing.

However, transfer of frozen embryos acts additively to statistically increase pregnancy rates from a single egg collection (fresh and frozen embryos), making embryo freezing a very useful method, as it also eases the economical and psychological burden of the couple.



Does it require preparation using drugs?

The transfer of frozen embryos to the uterus is programmed so that the uterine environment and the stage of the embryo are synchronized.

This programming intends to select the correct timing for implantation and on going pregnancy (implantation window).



Is it safe for the child?

The procedure is considered to be safe. All relevant studies on newborns born from cryopreserved embryos are reported to be healthy without a statistically important increase of congenital abnormalities.



Sperm freezing

Theoretically, sperm can remain in a frozen state indefinitely. A pregnancy was recently reported using sperm frozen 20 years ago.

Sperm freezing is recommended in the following cases:

  • Danger of loss of male reproductive capacity, i.e. testis removal for therapeutic reasons, chemotherapy, radiotherapy)
  • Absence of the male partner on the day of egg collection
  • Surgical sperm retrieval, to use as back up in order to avoid a further biopsy in a future cycle.
  • Electroejaculation
  • Ejaculation difficulty for psychological reasons
  • Progressive decline of sperm quality parameters
  • Vasectomy



Oocyte freezing

Oocyte freezing is an alternative solution that can be recommended to women with certain indications. Successful freezing of eggs promises many new applications. Nowadays, the number of young women surviving after chemotherapy or radiotherapy has increased.

These treatments are related with premature ovarian failure. Until today, the only acceptable option for these women was fertilization of their eggs using the male partner's sperm, which was not always possible for single unmarried women.

Until recently, egg freezing did not have an application in routine practice because eggs are particularly sensitive to freezing-thawing.

Modern developments in egg freezing are particularly encouraging as the improvement of cryopreservation media have lead to increased survival and fertilization of eggs following thawing, and ultimately increased pregnancy rates.

Following the international developments, Eugonia applies this method sparingly, informing and advising the patients on the pros and cons of the egg freezing.

 Back to top