Freezing Unfertilized Eggs Will Be Used In The Future

25.02.2011

Freezing embryos, women's eggs fertilized with sperm, has been done in IVF clinics for decades, but now science has improved upon freezing unfertilized eggs to use in the future.

Typically couples undergoing in-vitro fertilization produce several embryos and freeze those left over to be thawed later when they wish to try having more children.

In recent years scientists have figured out how to freeze and thaw unfertilized eggs from women, allowing them to freeze their eggs now and thaw them in the future, when they are ready to have children.

While some might have moral issues with the entire idea, imagine a young woman, diagnosed with cancer, who needs chemotherapy and radiation, which will leave her infertile.

If she wanted to preserve her fertility, she would have had to find a sperm donor to create an embryo, which could then be frozen.

Now, that woman can freeze her own unfertilized eggs and choose a partner when she is ready to try having children.

Another use is single women "preserving" their fertility, women like Kerri Oliveira, a career-driven woman in her early 30s.

"I have had a few relationships but haven't met the right person. I definitely want to have children in the next few years, but if that doesn't happen, at least I sort of have a backup plan," Oliveira said.

Her plan involves freezing her eggs at the IVF clinic, which will start offering egg freezing this summer.

"Being able to freeze eggs is breakthrough technology in that I can preserve my fertility and I can select a partner further down the road," Oliveira said.

Physicians and scientists at UConn just finished a clinical study on egg freezing that resulted in the birth of six babies.

While some clinics freeze eggs, not all have live births to prove that they can complete the thaw process.

"We are one of the few centers that have been able to produce results to show that this can be done with good success," UConn IVF lab director Dr. Claudio Benadiva said.

Their egg-freezing study had a live birth success rate of 46 percent, which is similar to rates for IVF.

Egg freezing is still considered to be experimental, but Dr. Benadiva said an internal review board, made up of experts, closely monitors UConn's program.

They consider the program's scientific merit as well as its ethical aspects.

One obstacle in perfecting egg freezing was in the thawing process, Dr. Benadiva said.

Ice crystals, similar to freezer burn, would form, damaging the egg's delicate genetic make up, which is much more fragile than an embryo.

A process called "vitrification" is used at UConn, which is similar to flash freezing.

Linda Siano, UConn's chief embryologist, performs the process by hand on each egg, which is like surrounding the delicate egg in a glass bubble for freezing.

Making UConn's egg freezing program unique is the fact that the woman who got the first live birth in 2002 using vitrification is the lab director.

Joni Stehlik changed the protocol she was using with another doctor at the time.

"I tweaked it a little bit and I got a pregnancy and he called me up and said, 'What did you do differently?' I said I changed the timing and the temperature and he said, 'whatever you did, it worked' and it hadn't worked before for him," Stehlik said.

Couples going through IVF might also freeze eggs.

There can be an ethical dilemma in creating more embryos than are implanted, Dr. Benadiva said.

Now, they can just freeze the woman's eggs to be thawed and fertilized later.

Egg donation is another front that grows from this advancement. Dr. Benadiva said we could one day see egg banks, similar to sperm banks, where women who cannot produce their own eggs could turn for a donor egg.

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