• Posted January 31, 2025

Fresh Better Than Frozen For IVF

Is fresh better than frozen?

Yes, when it comes to in vitro fertilization (IVF), a new clinical trial says.

Fresh embryo transfer appears to be a better option than using frozen embryos for women struggling to conceive via IVF, researchers reported Jan. 29 in The BMJ.

About 32% of women had a live birth following IVF with frozen embryos compared with 40% of those in the fresh embryo group, results show.

The frozen embryo group also had a lower rate of pregnancy – 39% versus 47% for fresh embryos, the study says.

These results run counter to the routine use of freezing all suitable embryos prior to transfer for women whose chances of IVF conception are low, researchers concluded.

“Fresh embryo transfer may be a better choice for women with low prognosis in terms of live birth rate compared with a freeze-all strategy,” wrote the research team led by Daimin Wei, a professor at Shandong University’s State Key Laboratory of Reproductive Medicine and Offspring Health in Jinan, China.

Women might have low odds of conception through IVF due to older age or low quantity or quality of eggs.

“The number of women who undergo IVF with low prognosis has been increasing and measures to improve the chance of live birth in these women are lacking,” researchers wrote.

Frozen embryos actually increase the chance of live birth in women with good IVF prognosis compared to fresh, researchers added.

However, evidence has been scarce regarding the best means of embryo transfer for women with a low IVF prognosis.

For the study, researchers compared results of fresh versus frozen embryo transfer in 838 women aged 33 to 34 with a low prognosis for IVF success.

The women were treated at nine fertility centers in China between December 2021 and May 2023, and were randomly assigned to either fresh or frozen embryo transfer. Their live birth rates were monitored until April 2024.

Pregnancy loss occurred in 31% of women in the frozen group, compared with 23% in the fresh group, results show.

Further, about 5% in the frozen group gave birth to live twins compared with 9% of the fresh group.

There were no differences in birth weight, obstetric complications, or illness risk in newborns between the two groups, researchers noted.

Further studies are needed “to explore the optimal number and stage of embryos for fresh transfer in women with low prognosis for IVF to have a singleton pregnancy,” the researchers wrote.

In an accompanying editorial, outside experts said they were concerned about potential biases that might have influenced outcomes.

“However, the process of freezing and thawing embryos is not without risks,” the editorial co-written by Simone Cornelisse with Radboud University in The Netherlands, noted. “Damage may occur during cryopreservation, storage, or thawing, and these steps can add substantial financial costs. Furthermore, treatment delays associated with elective freezing may be undesirable for some.”

More information

The Cleveland Clinic has more on IVF.

SOURCE: The BMJ, news release, Jan. 29, 2025