Egg & embryo freezing

Elective Egg Freezing

embryo freezingWomen are born with all the eggs they will ever have. The body does not “produce” eggs in the way that it produces sperm. Furthermore egg quality decreases with age, especially after the age of 35. As more and more women are delaying having children, egg freezing is a breakthrough technology that allows woman to freeze and store their eggs until such time as they are needed to be fertilised. This technology also holds promise for women with polycystic ovary syndrome (PCOS) , endometriosis and women with cancer (before undergoing any cancer treatment) who want to preserve their fertility

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.

Success Rates

Success rates are estimated at approximate overall 4% live-birth rate per oocyte thawed for cryopreservation using vitrification. E.g. if 10 eggs are frozen then there will be 40% chance of a live birth. As with standard IVF, success rates are linked to te age of the eggs being frozen.

It is reported that, on average, about 70% of the eggs frozen will survive the freezing and thawing process. Of the surviving eggs about 65% of these in turn will fertilise in response to ICSI (intra cytoplasmic sperm injection). The use of frozen eggs is still relatively new and it is difficult to provide accurate statistics for pregnancy rates. To date most eggs have been frozen without being used.

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.

The average cost of freezing eggs, including medication, the procedure and 5 years storage, is estimated at *R33 000.
*Costs may vary. Please discuss more accurate costs with the fertility clinic.

In order to further investigate the option to freeze your eggs, to understand the requirements and process for egg freezing or to review egg freezing in the news, you can follow the links below:

Medfem Clinic
011 4632244 and speak to Kim
Email: kim@medfem.co.za

More than a dozen frozen chances to be a mum – Kate Benson October 18, 2008

Embryo Freezing

Cryopreservation or freezing of embryos often occurs after IVF treatment where stimulation for additional eggs and thus sometimes embryos results. Freezing of embryos is only justified when there are good quality leftover embryos from an IVF cycle. The pregnancy success rate with frozen embryos transferred into the human uterus is approximately the same as with non-frozen embryos. However, some embryos do not survive the freezing process.

For many patients undergoing IVF (with or without donor eggs) the possibility for having to make a decision about what to do with additional embryos if often not considered or discussed. Fertility patients are, understandably, focused on creating embryos and not what to do with surplus embryos!
You need to discuss the policy of the Fertility Clinic with whom you are undergoing treatment, in order to ascertain what options will be available to you should you be left with surplus embryos after your treatment.

If you are an international client having your IVF in South Africa, you need to discuss transportation and/or storage of surplus embryos, and the costs involved, with your clinic upfront. Interestingly, there are over 500 000 frozen embryos on storage in the USA alone.

Options may include the following:

  • Freezing unfertilised eggs in an IVF cycle, instead of fertilising all eggs aspirated
  • Disposal – although many clinics will not allow disposal of embryos created in their laboratories
  • Placing the embryos back during the non-fertile part of a cycle – again, many clinics will not be open to performing this procedure
  • Donation to Research, specifically for stem cell research
  • Donation to another couple
  • Freezing indefinitely, here you need to consider the annual cost of freezing the embryo/s at -196 degrees Celcius. With this option it is also important that you make provision for the fate of the embryos in the event of your, your partner or both your deaths. It is also wise to decide upfront what should happen to the embryos in the case of divorce.

Frozen embryos are potential life and as such these decisions are suggested to be considered upfront.

Additional reading and information links: