In vitro fertilization frozen eggs less successful than fresh ones

Many fertility experts recommend cryo-preservation for women who want to become mothers in later life, because eggs harvested in relative youth are known to be healthier.

Kushnir warned that women who are planning to delay motherhood should be made aware by their health counselors that there are lesser chances of getting pregnant with cryopreserved eggs than using fresh ones.

“She further said, “‘Therefore, these women need to be counselled appropriately about all their options and if they in the end choose to freeze eggs, should freeze a large enough number to have a good chance of a future live birth”.

“We used to think that aging eggs were responsible for poor IVF success rates in older women, but here we show that it is more due to the aging of the egg’s environment”, Dr. Yanguang Wu, embyrologist and associate scientist at the Centre for Reproductive Medicine, said in the news release.

A new study, however, shows that freezing and thawing eggs could damage the cells and lower a woman’s chance of successfully carrying a child.

In January 2013, the American Society for Reproductive Medicine declared the technique of using frozen eggs for in vitro fertilization was no longer considered experimental.

The data set was based on voluntarily reported outcomes from 380 of 467 U.S.-based fertility centers, which in 2013 collectively performed 92 percent of all IVF cycles.

The workforce recognized 11,148 oocyte donation cycles, of which 2,227 (20%) concerned using cryopreserved oocytes, and the stay start charges of every IVF method have been in contrast. Frozen eggs, on the other hand, can be stored which gives women access to a wider range of donors and offers them greater flexibility in terms of scheduling and coordination.

On average, women who used fresh eggs had 1.7 embryos transferred per IVF cycle, compared with 1.6 embryos for women who used once-frozen eggs.

The study results don’t address the likelihood of births from eggs a woman freezes for her own later use. Even though frozen eggs are quite effective in the process of fertilization, they have a lower birth rate probability than fresh eggs. For instance, freezing eggs could be the best alternative for people planning to undergo treatments like chemotherapy, which could be toxic to eggs.

“Use of fresh eggs remains the gold standard since the pregnancy rates are superior and we have many years of experience and know much more about the safety of IVF with fresh eggs”, Kushnir explained to the outlet. However, the reason is still not clear to why frozen eggs resulted in fewer births. But it’s the first widespread study that compares live birth rates from frozen eggs to live birth rates from fresh ones. There may be something about the freezing and thawing process that degrades or otherwise harms the eggs, the study authors wrote.

In vitro fertilization implies the mixing of donor eggs from anonymous donors, usually young, with the sperm of the partner.