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Oocyte Freezing / Egg Freezing

Age negatively affects a woman’s egg supply, with the quality and quantity rapidly diminishing after the age of 32. Because the number of viable eggs decreases dramatically as a woman ages (commonly known as atresia), women may want to increase their chances of conceiving a child later in life by storing their viable eggs as early as possible. Risks of chromosomal abnormalities in offspring also increase with the age of a mother’s eggs. For this reason, it is best to use younger eggs for implantation rather than fresh older eggs.

Egg freezing, or oocyte cryopreservation, is ideal for women who have chosen to delay motherhood due to career, education or lifestyle choices, and for women who have yet to meet their life partner to share childbirth with. Women now have the ability to make personal choices regarding their fertility by selecting egg freezing as a means of securing their future potential for motherhood.

Women can opt for egg freezing for many reasons:

  • Those who are diagnosed with cancer who are about to begin chemotherapy or radiation. (Radio /chemo are toxic to gametes )
  • Those undergoing ART who do not consider embryo freezing as option .
  • Those who would like to preserve their future ability to have children.
  • Genetic conditions like Turner`s syndrome, Fragile X permutation and deletions of X chromosome as they have risk of premature ovarian failure .
  • Oocyte banking for purpose of donation .
  • Defer child bearing for career, financial and social reasons .
  • In some countries where embryo freezing is not allowed for ethical and religious reasons

During this process ,woman is stimulated with hormone injections for 10-12 days and serial ultrasound scans done .Once the eggs are ready ,trigger injection is given for maturation of eggs and  eggs are retrieved after 35 hours under transvaginal ultrasound guidance under anaesthesia. Oocytes are then vitrified and stored in liquid nitrogen till the woman wishes to conceive. These oocytes are later thawed and injected with sperms by ICSI procedure which fertilizes the egg resulting in embryo formation which can be transferred into the womb to give pregnancy.

Vitrification is a process of fast freezing with extreme cooling thereby preventing ice crystal formation inside the oocyte which could be cell damaging. This method has now replaced slow freezing technique which was often cell damaging.

The success rate is of greatest interest to women undergoing this procedure. If eggs are frozen at age < 35years ,then success rate is between  61-77% where as it is 18-40% if woman is >35 years at the time of egg freezing. Thus egg freezing at younger age is recommended by fertility experts for the security they seek. It is recommended to freeze atleast 20 eggs to give a reasonable chance of one take –home baby, as egg freezing is a leaky process where some eggs and embryos are usually lost at each stage of the process.

Egg freezing procedure is absolutely safe for women and  babies born of it. It should be ideally done by a fertility centre with enough expertise in this field. Perhaps the greatest risk, however ,is for a woman to be given false hope that leads her to put off childbearing . One has to understand that these procedures do not offer 100% take home baby rates. Hence it is best to conceive at a younger age and these procedures be limited to medical indications to the extent possible and not entirely for career oriented reasons.

Till date, over 5,000 babies have been born from frozen egg cycles. Of the women who partnered in this fertility preservation and frozen egg IVF cycle, 65 percent achieved successful pregnancies.