Oocyte cryopreservation

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article reads like a press release or a news article and may be largely based on routine coverage. Please help improve this article and add independent sources. (March 2015) This article contains wording that promotes the subject in a subjective manner without imparting real information. Please remove or replace such wording and instead of making proclamations about a subject's importance, use facts and attribution to demonstrate that importance. (March 2015) (Learn how and when to remove this template message) (Learn how and when to remove this template message)

Oocyte cryopreservation is a procedure to preserve a woman's eggs (oocytes). This technique has been used to postpone pregnancy. When pregnancy is desired, the eggs can be thawed, fertilized, and transferred to the uterus as embryos. Several studies have shown that most infertility problems are due to germ cell deterioration related to aging.^[1] The procedure's success rate varies depending on the age of the woman, with the odds being higher in younger, adult women.

Indications

Oocyte cryopreservation can increase the chance of a future pregnancy for four key groups of women:

1. Those diagnosed with
   radiotherapy
2. Those undergoing treatment with assisted reproductive technologies who do not consider embryo freezing an option
3. Those who would like to preserve their future ability to have children
4. Those with ovarian diseases such as PCOS

Over 50,000 reproductive-age women are diagnosed with cancer each year in the United States.^[2] Chemotherapy and radiotherapy are toxic for oocytes, reducing the amount of viable eggs. Egg-freezing may be used in this case to preserve eggs.

Oocyte cryopreservation is an option for individuals undergoing IVF who object, either for religious or ethical reasons, to the practice of freezing embryos. In this way, there are no excess embryos created, and there need not be any disposal of unused frozen embryos.

Additionally, women with a family history of early menopause may have an interest in fertility preservation to preserve viable eggs that could deteriorate at an earlier onset.

In 1986, the first human birth of oocyte cytopreservation was reported.

Method

The egg retrieval process for oocyte cryopreservation is the same as that for

Immature oocytes have been grown until maturation in vitro, but it is not yet clinically available.^[7]

Success rates

Early work investigating the percentage of transferred cycles showed lower frozen cycles compared with fresh cycles (approx. 30% and 50%),^[8] however more recent studies show "fertilization and pregnancy rates are similar to IVF/ICSI (or (in vitro fertilization/intracytoplasmic sperm injection) with fresh oocytes when [both when] vitrified and warmed oocytes are used as part of IVF/ICSI".^[9] These studies were completed mostly in young patients.

In a 2013 meta-analysis of more than 2,200 cycles using frozen eggs, scientists found the probability of having a live birth after three cycles was 31.5 percent for women who froze their eggs at age 25, 25.9 percent at age 30, 19.3 percent at age 35, and 14.8 percent at age 40.^[10]

Two 2000s studies showed that the rate of

In the fall of 2009, The American Society for Reproductive Medicine (ASRM) issued an opinion on oocyte cryopreservation concluding that the science holds "great promise for applications in oocyte donation and fertility preservation" because recent laboratory modifications have resulted in improved oocyte survival, fertilization, and pregnancy rates from frozen-thawed oocytes in IVF.[13] The ASRM noted that from the limited research performed to date, there does not appear to be an increase in chromosomal abnormalities, birth defects, or developmental deficits in the children born from cryopreserved oocytes. The ASRM recommended that pending further research, oocyte cryopreservation should be introduced into clinical practice on an investigational basis and under the guidance of an Institutional Review Board (IRB). As with any new technology, safety and efficacy must be evaluated and demonstrated through continued research.

In October 2012, the ASRM lifted the experimental label from the technology for women with a medical need, citing success rates in live births, among other findings. However, they also warned against using it only to delay child-bearing.

In 2014, a Cochrane systematic review was published. It compared

Immature oocytes have been grown until maturation in vitro at a 10% survival rate, but no experiment has been performed to fertilize such oocytes.^[7]

Cost

The cost of the egg-freezing procedure (without embryo transfer) in the United States, the United Kingdom, and other European countries varies in between $5,000 and $12,000. The cost of egg storage can vary from $100 to more than $1,000. Provisional health programs do not cover social egg freezing. Furthermore, no provinces provide funding for IVF after social egg freezing.^[15]

Medical tourism may have lower costs than performing egg freezing in high-cost countries like the US. Some well-established medical tourism and IVF countries such as the Czech Republic, Ukraine, and Cyprus offer egg freezing at competitive prices. It is a lower-cost alternative to typical US options for egg freezing. Spain and the Czech Republic are popular destinations for this treatment.

Iranian insurance started to pay insurance incentives for women freezing their eggs in 2024.^[16]

History

Elective oocyte cryopreservation, also known as social egg freezing, is non-essential egg freezing to preserve fertility for delayed child-bearing when natural conception becomes more problematic. The frequency of this procedure has steadily increased since October 2012 when the American Society for Reproductive Medicine (ASRM) lifted the 'experimental' label from the process.^[21] There was a spike in interest in 2014 when global corporations Apple and Facebook revealed they were introducing egg freezing as a benefit for their female employees.^[22] This announcement was controversial as some women found it empowering and practical, while others viewed the message these companies were sending to women trying to have a successful long-term career and a family as harmful and alienating. A string of "egg-freezing parties" hosted by third-party companies have also helped popularize the concept among young women.^[23] Social science research suggests that women use elective egg freezing to disentangle their search for a romantic partner from their plans to have children. ^[24]

In 2016, then US Secretary of Defense Ash Carter announced that the Department of Defense would cover the cost of freezing sperm or eggs through a pilot program for active duty service members, to preserve their ability to start a family even if they sustain certain combat injuries.^[25]

There are still warnings for women using this technology to fall pregnant at an older age as the risk of pregnancy complications increases with a mother's age. However, studies have shown that the risk of congenital abnormalities in babies born from frozen oocytes is not increased further when compared to naturally conceived babies.^[26]

Risks

The risks associated with egg freezing relate to the administration of medications to stimulate the ovaries and the procedure of egg collection.

The main risk associated with the administration of medications to stimulate the ovaries is ovarian hyperstimulation syndrome (OHSS). This is a transient syndrome in which there is increased permeability of the blood vessels, resulting in fluid loss from the vessels into the surrounding tissues. In most cases, the syndrome is mild, with symptoms such as abdominal bloating, mild discomfort, and nausea. In moderate OHSS there is increased abdominal bloating resulting in pain and vomiting. Reduced urine output may occur. Severe OHSS is serious with even further bloating so that the abdomen appears very distended, and thirst and dehydration occur with minimal urine output. There may be shortness of breath and there is an increased risk of DVT and/or pulmonary embolism. Kidney and liver function can be compromised. Hospitalization under specialist care is indicated. There is no treatment for OHSS, supportive care until the symptoms naturally resolve is required. If an hCG trigger has been used with no embryo transfer, OHSS usually resolves in 7–10 days. If an embryo transfer has occurred and pregnancy results, the symptoms may persist for several weeks. Doctors reduce the likelihood of OHSS occurring by decreasing the doses of gonadotropins (FSH) administered, using a GnRH agonist trigger (instead of an hCG trigger), and freezing all embryos for transfer rather than conducting a fresh embryo transfer.

Risks associated with the egg collection procedure relate to bleeding and infection. The collection procedure involves passing a needle through the wall of the vagina into vascular-stimulated ovaries. A small amount of bleeding is inevitable. In rare cases, there is excessive bleeding into the abdomen requiring surgery. Women undergoing the procedure must advise their specialist of all medications, including herbal supplements, they are using so the specialist can assess whether any of these medications will affect the ability of the blood to clot. Concerning infection, provided the woman does not have additional risk factors for infection (suppressed immune system, use of immuno-suppressive medications, or large ovarian endometriomas) the risk of infection is very low.

One additional risk of the ovaries being temporarily increased in size is ovarian torsion. Ovarian torsion occurs when an enlarged ovary twists around on itself, cutting off its blood supply. The condition is excruciatingly painful and requires urgent surgery to prevent the ischemic loss of the ovary.

See also

• Egg donation
• Semen cryopreservation
• In vitro fertilization

References