Can you freeze eggs in an attempt to preserve fertility for a future pregnancy?

• Yes, egg freezing (oocyte cryopreservation) is being done – some women freeze eggs to try to reduce the impact of aging on fertility
• Success rates for IVF with fresh eggs are high in young women
• Success rates for IVF using frozen eggs are generally much lower – but are improving. This technology is rapidly evolving.

There is currently controversy about:

• Who should be offered egg freezing?
• What should women of different ages be told about their chances for having a baby with frozen eggs?
• Are women who freeze eggs well informed about the chances to have a baby in the future with their frozen eggs?

What do recent studies show regarding pregnancy success rates using frozen eggs?

Egg freezing is relatively new

• IVF with fresh eggs has reportedly resulted in the birth of about 3 million babies worldwide
• IVF with frozen eggs has resulted in the birth of about 2000 babies worldwide
• Studies continue to investigate whether the older “slow freezing” technology or the newer method of “vitrifying” eggs will be better

Older studies

• Studies from the 1990′s to early 2000′s showed pregnancy success rates with frozen eggs of about 2% to 10% (live birth rate per embryo transfer cycle).

Recent studies

• A recent study from an Italian group found similar fertilization and embryo development rates of vitrified versus fresh eggs. Vitrification is a relatively new freezing method.
  • This study involved 40 cycles in women (average age 35.5)
  • The ongoing pregnancy rate (beyond 12 weeks of pregnancy) with vitrified eggs was 30% per cycle.
  • This is a good rate since only 3 eggs can be inseminated under Italian law.
    • Study by L Rienzi, et al, Human Reproduction; January 2010

• A 2009 study of 23 IVF cycles using frozen eggs (average age 31.5)
  • There were 14 pregnancies, 1 miscarriage and 13 ongoing pregnancies (57% per transfer)
    • Study by J Grifo and N Noyes, Fertility and Sterility; May 2009

• A large multicenter Italian study compared IVF using fresh vs. frozen eggs
  • Italian IVF clinics tend to have lower success rates because only 3 eggs can be inseminated per cycle (by law)
  • They compared 2209 cycles with fresh eggs to 940 cycles with frozen eggs
  • The success rate was halved using frozen instead of fresh eggs
  • 748 thawing cycles in women less than 39 years old (average age 33.6)
    • Live birth rate per transfer with frozen eggs was 13.3% (age < 39)
  • 192 thawing cycles in women 39 and older (average age 40.5)
    • Live birth rate per transfer with frozen eggs was 8.1% (age 39+)
  • Study by A Borini et al, Fertility and Sterility; January 2010

Aging and female fertility issues

Many women pursue advanced education and career advancement – and delay childbearing. Fertility specialists commonly see women with fertility issues due to aging in their late 30′s and 40′s who  are disappointed when told that it may be too late to have a baby with their eggs.

When an “older” woman switches to using “young” donor eggs, she is very likely to have a successful pregnancy outcome. Some women are comfortable moving on to using donor eggs to have a baby. For others, using their eggs is critical.

Think of the uterine lining as the “garden”  and the embryos as “plants”:

• Aging does not compromise the garden
• Aging “weakens” the plant
• That is why success rates with egg donation are so high – regardless of the age of the recipient woman
• Egg freezing could let women extend their biological clock and delay childbearing for social or professional reasons.
• Women could “self-donate” eggs – freeze and store them for the future in case they age significantly by the time they want a baby.

Risks of egg freezing to the woman donating are low:

• Women are stimulated with medications as for IVF to produce multiple eggs prior to aspirating eggs from the ovaries and freezing.
• The rate of serious complication (severe ovarian hyperstimulation, serious bleeding, infection, etc.) is less than 1%.
• There is the risk that women might delay having children because they have frozen eggs that they expect to have success with. Some would have poor results later after thawing, fertilization and embryo development.

Questions and potential problems with elective oocyte cryopreservation to  delay childbearing

• Do the women have realistic expectations of the pros and cons and alternatives to freezing their eggs?
• What effect would deferral of childbearing with egg freezing have on our society if it becomes common?
• Will some fertility doctors mislead women about benefits of this process for their own economic gain?
• Is it proper to allow women to make their own decisions about using this new technology now, or should “social” egg freezing to extend fertility be reserved for the future – after we have better outcome studies?
• At what point is an “experimental” procedure done enough, understood enough, and researched enough so that it is no longer considered experimental?

The definition of ‘‘experimental procedures’’ according to the Practice Committee of the American Society for Reproductive Medicine (ASRM):

• “Procedures (including tests, treatments, or other interventions) for the diagnosis or treatment of infertility will be considered experimental or investigational until the published medical evidence regarding their risks, benefits, and overall safety and efficacy is sufficient to regard them as established medical practice.”

What is the position of the American Society for Reproductive Medicine (ASRM) regarding egg freezing?

It appears that the current position of the ASRM is:

• Egg freezing is appropriate for women with cancer and other medical conditions needing treatment that is likely to impair their fertility.
  • These women usually do not have any other good option for having a baby with their own eggs.
• ASRM currently discourages egg freezing for women who want to electively extend their fertility into the future. Apparently, this is due to concern that there is some risk, and could even be harm done by using new technology prematurely.
  • “Prematurely” means before both safety and efficacy have been reasonably established.
• When eggs are frozen, it should only be done with appropriate informed consent in an IRB approved study protocol.
• There is not enough data to properly inform women about chances for success using frozen eggs.
• There is not enough data to know if egg freezing might cause an increase in problems in children.

Conclusions about egg freezing

• Egg freezing for extending female fertility is showing great potential for the future.
• It is currently being used for women with cancer that need treatments that impair their future fertility.
• Some IVF clinics are offering social egg freezing to extend fertility.
• Although some recent studies report good success rates for IVF with “young” frozen eggs, there is little data on success rates using “older” eggs.
  • Women considering freezing eggs tend to be in their late 30′s and early 40′s.
  • We need more outcome data using frozen eggs in this age group.
• This is an evolving technology with important questions still to be answered before it is “ready for prime time”.

The Advanced Fertility Center of Chicago is currently involved in an IRB approved study on egg freezing using vitrification technology.

• Read more about our egg vitrification study
• Call us  for details about enrolling in this study.
  • 847-662-1818

Richard Sherbahn, MD is a fertility doctor practicing in the Chicago, Illinois area. Connect with me on Google+

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