Egg Freezing

November 12, 2012

Egg Freezing

Fertility is limited by biology as the quality and supply of the eggs of women reduce as they age. Egg freezing is in demand because for many women they want to have a healthy and successful pregnancy later.

Women who are over the age of 35 who plan to have children now have an opportunity to have their eggs stored at a time when they are most productive. These can then be used when they decide to start or increase their family.

Previously it was difficult to freeze eggs successfully. This was because the ice crystals developed in the egg at the time of the freezing process. The reliability of the egg was compromised and the fertilization was difficult because the outer membrane of the egg became hard.

There are now breakthroughs in egg freezing. There is a culture media system which protects the egg being damaged during the thawing and freezing process. This new system causes the egg to dehydrate during the process of freezing, then during the thawing process it is rehydrated.

Another technique is Intra Cytoplasmic Sperm Injection or ICSI. The egg is injected with a single sperm by an embryologist in order to fertilize it.

This development to freeze eggs has led to an increase in successful pregnancies from eggs which have been frozen. According to reports the figure is up approximately 35% for each transfer of embryo and as a result there has been an increase in the amount of babies born worldwide, from eggs which have been frozen, to more than 200.

The American Society for Reproductive Medicine considers egg freezing procedures to be at the investigation stage. Some scientists say that because of the advances in cryopreservation the survival rates in the post-thaw process is as about 90% and the rates of fertilization are approximately 80%.

Egg freezing can be used to postpone pregnancy for women. This was only made possible by discovering the importance of the age of the eggs rather than the biological age of the woman. Women of post-menopausal age can become pregnant and deliver a baby by using the donor eggs which are from a woman of a younger age. This encouraged the preservation of eggs for women who are young. Fertility in women is highest at 27 years of age. The chance of a woman getting pregnant after 40 years of age is below 10%. Carrying out egg freezing and harvesting allows women to become pregnant later. It appears egg freezing will have an effect on the donation of eggs by letting the one donor store eggs which could be used by a number of women. There is a school of thought where the current use of egg freezing benefits women who have diseases or illness which affects their fertility.

The procedure used in freezing eggs varies between laboratories. To produce a multiple amount of eggs women are given medication and an ultrasound guided needle is used to harvest the eggs from the ovary. A microscope is used to identify the individual eggs which will be frozen. Damage can be caused to the eggs by ice crystals so technicians will take out the water and the eggs will receive a solution to prevent this from occurring. Eggs can be frozen by freezing the egg slowly and the faster technique is known as vitrification. Eggs which have been frozen are kept in a storage tank which contains liquid nitrogen.


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