Fertility Preservation Foundation - Michigan

Egg and Embryo Freezing 101

Egg and Embryo Freezing

Egg and Embryo freezing are often the best most assured ways of preserving future fertility for a female facing cancer treatment that could significantly damage their ovaries. Egg and embryo freezing both are similar in that first the patient is given fertility stimulating medication to stimulate the development of multiple eggs and then the eggs are retrieved via ultrasound guided transvaginal needle aspiration while the patient is anesthetized.

The mature, or good eggs are then frozen for future use. For embryo freezing patients, the eggs are first fertilized with sperm and then after growing for approximately five days in the lab they are frozen at what is called a blastocyst stage. Once eggs are retrieved, the patient can then start their cancer treatments.

Eggs can be used years later after successful cancer treatments are complete. Eggs are thawed and then fertilized with sperm. The embryos are then grown in the invitro fertilization (IVF) lab for five days. Transfer of a single embryo to the patient’s uterus is then performed. If a patient froze embryos, then a single embryo is thawed and transferred to the patient’s uterus.

Pregnancy Success

Pregnancy success depends on several factors, the most important being egg/embryo quality. The major factor effecting egg/embryo quality is age of the woman when the eggs were retrieved and number of eggs available. In young patients <35, pregnancy success rates with a blastocyst embryo can be 40-70%.

Effect on Offspring conceived with frozen thawed Oocytes.

Most studies have not shown an increase in congenital anomalies in children conceived from frozen eggs compared to those conceived from fresh eggs. However, more long-term studies are needed to further assess risks.

How Long can Eggs and Embryos be stored?

Embryos frozen up to 25 years have resulted in successful pregnancies. Egg freezing is a newer science, so successful pregnancy after thawing frozen eggs has occurred in eggs frozen up to approximately 5+ years. There is no reason to believe successful egg freezing time will be different from what has been seen with embryos.

More Information About Egg and Embryo Freezing

More information is available from The American Society of reproductive medicine at www.ASRM.org. In Michigan, we recommend information from The Fertility Center in Grand Rapids, the Oncofertility consortium at Michigan State University, and the University of Michigan Fertility Center as additional sources of information.

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