Egg Freezing
Banking Your Eggs: Beating The Biological Clock
Egg Freezing |
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Other Names: Egg freezing is also called egg banking and oocyte cryopreservation.
What Is Egg Freezing? Egg freezing is a medical technique where a woman's eggs are surgically removed from her ovaries and frozen for future use. When a woman is born, she is born with all the eggs she will ever have. As she ages, the number and quality of those eggs begin to decline. Women who want to delay having children until they are older can have some of their eggs frozen while they are still in good shape. These younger eggs are less likely to be damaged so if they are used later, the risk of having a child with a birth defect is lower. This is why women who conceive naturally after the age of 40 have a much higher risk of having a baby with Down syndrome.
Who Are Candidates For Egg Freezing? Elective Freezing Other Reasons Egg freezing is a relatively new practice, scientists have been freezing sperm for decades, and embryos for the last 20 years. Egg freezing has some catching up to do. The main problem is that eggs don't freeze particularly well. They contain a lot of water which crystallizes when frozen and damages the chromosomes in the cell (an egg is only one cell in size). Antifreeze agents can be used to prevent this, but they contain cytotoxic, an agent that damages cells. For this reason, the American Society for Reproductive Medicine (ASRM) labeled egg freezing 'experimental'. However, after some research the ASRM lifted this label in 2012, stating: Only specialized fertility clinics offer egg freezing services. Once you have selected a clinic, a doctor will assess your health and carry out a blood test to check your fertility. By taking a sample of blood, the clinic will measure the levels of Inhibin B - a hormone produced by your ovaries. The more you have, the more eggs left in your ovaries. Next you will be given fertility drugs (the same types of drugs given to women going through IVF) for 8 to 14 days. The purpose of these drugs is to stimulate your ovaries into releasing lots of eggs (typically you only release one a month). While taking the drugs you will be monitored closely by ultrasound scan and blood tests to check your response to ovarian stimulation. After 8 to 14 days, the eggs will be ready for retrieving. A final injection of HCG will be given to boost the maturation of the eggs so that they are released on schedule. Shortly after collection, the unfertilized eggs are cooled to subzero temperatures. An antifreeze solution called cryoprotectants protects the eggs from forming harmful ice crystals. However, as we discussed earlier, these cryoprotectants tend to be cytotoxic. The science of freezing eggs is all about how to remove the water from the cell as quickly as possible, without damaging it. To get around this, embryologists have developed a slow-freeze method. The temperature is gradually reduced, with lower concentrations of cryoprotectants to begin with. As the temperature gets colder and the egg's metabolic rate declines, they add higher concentrations of cryoprotectants. On average, about 20 eggs will be removed for freezing. 6 to 8 eggs will be thawed for each attempt at pregnancy. How Long Can Eggs Be Frozen For? Eggs can be stored for up to 10 years in liquid nitrogen - rather like a deep freeze. What Happens When I Want To Use My Frozen Eggs? When you decide to use your eggs, they will be thawed, fertilized in a lab with sperm and implanted via IVF into your womb. You may use your partners sperm for the fertilization, or if you don't have a partner, a donor's sperm. In both cases thawed eggs can only be fertilized using ICSI procedure - this is where the sperm is injected directly into the egg. What Are The Pregnancy Success Rates? About 75 to 80 percent of eggs survive freezing and thawing. A similar amount will be fertilized successfully. The chances of becoming pregnant after IVF treatment is about 40 to 50 percent. It depends on what age you had your eggs frozen at. How Much Does Egg Freezing Cost? Typically it costs between $8,000 and $12,000. You will need to pay an additional $2,000 to $4,000 for your fertility medications. Also, you will need to pay a few hundred dollars every year for egg banking costs. Are There Any Risks To Babies Born From Frozen Eggs? According to the ASRM, there is enough preliminary information to say that this technique is safe. The ASRM committee who investigated egg freezing concluded that there were no increase in birth defects or chromosome abnormalities in children born to oocyte cryopreservation. Yet, this point is hotly debated. Some studies suggest that babies born to any ART procedure (assisted reproduction technology) are at risk of rare disorders such as the neurological condition Angelman syndrome. The risk can be reduced by pre-implantation genetic diagnosis (PGD). PGD is a way to test the embryo for genetic problems before implantation. How Do I Find Out More About Egg Freezing? United States United Kingdom
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For more related procedures, see the following: • Extracting sperm for IVF: Sperm aspiration. Back to Homepage: Womens Health Advice
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