Cryopreservation of oocytes and embryos — two different techniques used in IVF and increase the success of it. Let’s see and discuss their main features.
What is oocyte cryopreservation?
This method is considered a kind of experimental technology. The thing is that often when holding the level of survival of oocytes after freezing is very low. In addition, germ cells, after thawing and spaces on a nutrient medium, are not always able to be fertilized.
The feasibility of this method can be justified only in the case when the woman has no sexual partner or are not yet ready to become a mother. In such situations, it is perhaps the only chance to get pregnant and give birth to a child. As agents used for freezing oocytes, may act as cryoprotectants such as ethylene glycol and dimethyl sulfoxide. In this way can be performed, the cryopreservation of oocytes. It should be noted that the storage duration has no impact on survival.
It all depends on the so-called structural complexity of oocytes. Therefore, before carrying out such procedures, an important importance is a thorough selection process, which is carried out by visual inspection of oocytes in a special microscope.
According to the statistical observation, the frequency of survival of frozen oocytes is approximately 68%, while the fertilization rate them – 48%. If we talk about the frequency of prenatal care for each frozen oocyte, were observed in 2% of cases.
What is embryo cryopreservation?
This type of freezing biological material for follow-up IVF procedure is more progressive. The fact that embryos are amenable to cryopreservation is much better.
The use of this technique allows the procedure of in vitro fertilization in one cycle. So, if after transplantation of the cultured embryo, the pregnancy does not occur, it is possible to use cryopreserved and not to new cultivation on a nutrient medium.
Cryopreservation of embryos has its pros and cons. The advantages include:
- reducing time and material costs for IVF (nutrient medium expensive);
- reducing the length of the procedure;
- the possibility of a repeat IVF after a long time.
The main disadvantages of this method include the fact that the probability of pregnancy is about 60% and survival rate of embryos after their thawing is of great fluctuation, from 35 to 90%. Given these facts, it is difficult to predict how the implantation of embryos after cryopreservation.