Egg Cryo-Preservation



Egg (Oocyte) Freezing


What Is Egg Freezing?


Egg freezing is a breakthrough technology that allows women to freeze and store their eggs until a pregnancy is desired, at which time the eggs are thawed, fertilized and transferred to the uterus as embryos. These new developments offer the hope of preserving fertility for a large number of women.


Netcells has partnered with Medfem, one of the top Infertility Clinics in SA, to offer storage of human eggs (oocytes).


Background


Human sperm and embryos have been routinely cryopreserved in conjunction with Assisted Reproductive Technology programs since the first birth from frozen- thawed human sperm was reported in 1953 and the first pregnancy after cryopreservation of a human embryo was reported in 1983. Successful cryopreservation of human eggs has proved more difficult. Because of their size and unique structural characteristics, eggs are more susceptible to damage during freezing than sperm or embryos.


The first pregnancy originating from a frozen – thawed and fertilized human egg was reported in 1986 which was soon followed by the first live birth reported in 1987. Egg freezing has been relatively unsuccessful, until recently.


Who might benefit from egg cryopreservation?


Egg freezing is used in the following situations:


  • Fertility preservation in young women giving them a wider choice of their reproductive timing - Women may need or wish to postpone their childbearing age to after 35 years of age. Today, women are feeling the pressure of having to choose between a career and a family. Some are returning to school or pursuing advanced degrees and don’t know when or if they will have children. For many, it may simply be an issue of not having found the right partner yet. Ovarian failure is one of the leading causes of infertility today due to delayed childbearing. Fertility potential declines, as a woman gets older due to poorer egg quality. This decline in fertility is significant after age 35 and is very drastic after age 39.
  • Women in the reproductive-age group that are diagnosed with cancer will need surgery, chemotherapy and/or radiation treatments that can typically lead to infertility by destroying the eggs. While options vary depending on age, type of cancer and cancer-treatment plan, egg freezing can provide these women the opportunity to preserve their fertility. If diagnosed with cancer then the patient needs to contact Medfem Fertility Clinic urgently for a fast track appointment. The process of egg collection must take place BEFORE any form of therapy takes place.
  • Women suffering from endometriosis, a progressive disease that can impair ovarian function. The disease is becoming far more common in the western world, particularly among younger women.
  • Egg donation - Women who like to donate their eggs to assist others with reproduction.
  • Religious or moral objection to freezing embryos – couples undergoing IVF with concerns over embryo cryopreservation. Frequently, in routine IVF, any excess embryos that remain are frozen for future use. However, if they are not to be used, their disposal can create a difficult ethical issue. The ability to freeze unfertilized eggs offers a positive solution for many people.
  • Male partner unable to produce a semen sample at the time of oocyte retrieval.

How does egg cryopreservation work?


Unlike sperm and embryo cryopreservation, which have become routine processes in assisted reproductive technology, success with freezing eggs has historically been difficult to achieve. This is because the egg is the largest cell in the human body and contains a considerable amount of water. When eggs are frozen, ice crystals form that can destroy the cell. To prevent this, the eggs are “vitrified”. Vitrification is a process whereby a cryoprotectant agent (dimethyl sulphoxide – DMSO) is added and the egg is then rapidly frozen in such a way as to prevent ice crystals within the egg that could shatter the delicate structure of the egg.