Egg freezing is the process of freezing mature or immature oocytes below sub-zero temperatures. These oocytes can be thawed & matured under in vitro conditions & can be fertilized using appropriate technique. Good pregnancy rate have been seen from such embryos derived from oocyte freezing. In view of the fact that the egg freezing has drawn a lot of attention in the field of reproductive medicine, the indications for oocyte freezing are given below.
- Women of reproductive age undergoing chemotherapy for cancer treatment.
- Unable to get sperm for IVF/ICSI during treatment
- Egg donation programme
- When women wish to have family in the later stage due to their personal reasons.
- History of premature ovarian failure (POF)
- In PCOS patients when stimulation is merged with in vitro maturation (IVM) method.
Process of freezing
After egg retrieval, the embryologist (an expert in oocyte freezing) will wash & incubate the oocytes for approx 2 hrs. The process starts with the denudation in which the cumulus cells which surrounds the oocytes are denuded to know the maturity of eggs. During the freezing process, oocyte has to undergo various biological changes. Firstly, it is treated with Equilibration Solution (ES) – high concentration of penetrating cryoprotectants like glycerol DMSO, propanediol, etc which replace the water content of cell with cryoprotectants. Then the oocytes are treated with Vitrification solution (VS) which is a combination of permeating & non-permeating agents (Rafflose, Trehalose, etc). Then it is directly exposed to liquid nitrogen. Due to this highly viscous medium its forms a glassy substance at low temperature. The procedure is very rapid any delay can cause damage to the oocytes like spindle damage etc.
Advantages of Oocyte freezing:
- Social egg freezing offered to women under the age of 38 yrs who want to start their family at later stages. It adds a possibility to have a healthy & genetically related child.
- Fertility preservation for young women with cancer.
- Reduces need of a donor
- Reduces the number of treatment performed at advanced maternal ages.
A couple needs to understand the impact of age on their fertility. Egg freezing is an alternate option for those people who are facing such kind of problems as discussed in the above article.
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