Cryopreservation – Egg Freezing
Egg freezing at a glance
- Egg freezing, also called human oocyte cryopreservation, is a rapidly advancing technology of extracting, freezing and storing a woman’s eggs (oocytes). The eggs can later be thawed, fertilized, and transferred to the uterus as embryos months or years later.
- Women may consider freezing their eggs if: they have been diagnosed with cancer and have not yet started treatment, they are undergoing fertility treatment, or they would like to preserve their future ability to have children.
- Reproductive cryopreservation is not new. Medical clinics have been freezing sperm since the 1950s and embryos since the 1980s. Doctors in Australia reported the world’s first pregnancy using frozen oocytes in 1984.
What is egg freezing?
While sperm and embryo cryopreservation have become routine, egg freezing has developed at a slower pace, largely due to the high water content of eggs, risking cellular damage through the freeze-thaw process. Until recently, pregnancy rates from egg freezing were a fraction of those from traditional in vitro fertilization (IVF) using either fresh or frozen embryos. However, pregnancy rates using embryos created from formerly frozen oocytes are climbing, and it may not be long until they become much closer to rates for cryopreserved embryos.
Egg retrieval for oocyte cryopreservation is similar to that for in vitro fertilization (IVF). After an evaluation of overall and reproductive health, the woman takes ovulation inducing medication. The goal is to stimulate her ovaries to produce a sufficient amount of eggs in one cycle for retrieval. The retrieval procedure is a minor out-patient surgery conducted in a clinic with mild sedation.
Though the largest cell in the human body, the human egg is also very fragile. Some will undoubtedly be lost in the freezing and thawing processes. Much research is underway into new ways to bring eggs successfully through the cryopreservation process.
When the woman is ready to attempt conception, an embryologist thaws her eggs and uses intracytoplasmic sperm injection (ICSI) to fertilize those surviving the thaw. A physician then transfers the resulting embryos into her uterus.
Physicians and scientists have documented hundreds of births from oocyte cryopreservation worldwide, and rates of birth defects and chromosomal defects have been comparable to that of the general population.
While many in the scientific community still consider egg freezing to be experimental, fertility specialists also share much optimism that it provides options for groups of women who might otherwise have few or none.
The total cost to utilize egg freezing to achieve a pregnancy is comparable to that of IVF – from $12,000 to $20,000. Clinics also charge a separate egg storage fee of about $500 annually.
Who needs egg freezing?
Three groups can benefit from oocyte cryopreservation:
- Women diagnosed with cancer who have not yet begun chemotherapy or radiotherapy.
- Women undergoing treatment with assisted reproductive technologies who do not consider embryo freezing an option for religious and/or moral reasons.
- Women who would like to preserve their future ability to have children, either because they do not yet have a partner, or for other personal or medical reasons.
Because cancer treatments are often toxic to oocytes, egg freezing offers women diagnosed with cancer the chance to preserve their eggs so that they can have children in the future.
In addition, some healthy women undergoing IVF object to the practice of freezing excess embryos. Oocyte cryopreservation allows them to fertilize only the minimum number of eggs needed for a single treatment cycle, freezing additional eggs for later use. This way, no excess embryos are created.
Thirdly, many women choose egg freezing in order to focus on other pursuits – such as education, career or travel – with plans to attempt childbearing later. Freezing healthy eggs at an early age may optimize chances for a future pregnancy.
Also, young women with a family history of premature menopause can freeze their eggs in case their eggs are depleted at an early age.
Who is a good candidate for egg freezing?
In general, any person who is a candidate for conceiving with their own eggs via IVF, is likely to be a good candidate for egg freezing. Also like IVF, success rates are better for those who are younger (ideally less than 35) and who have good ovarian reserve markers (AMH, AFC, FSH).
We have identified certain clinical situations where we feel the chance to have a successful egg freezing cycle and subsequent pregnancy is good. We recommend considering treatment if you are in one of these groups.
- Ideal age 35, but allowed up to age 43 if other parameters are met.
- Women with:
- FSH < 12
- AMH >1.0
- AFC > 8
Success rates for egg freezing
The Reproductive Science Center of the Bay Area is a leading pioneer in infertility treatments including IVF with egg donation and LGBTQ family building. We’ll work with you to help you achieve your dreams of having a baby.