Both Frozen Or Fresh Embryos Work Well For IVF In Most Women

Using frozen embryos for in-vitro fertilization (IVF) is as effective as using fresh embryos, an Australian study has found. The researchers then compared the rates of live birth between the two groups.

Before freezing methods were refined, fresh embryos were the only option, but as cryopreservation techniques improved, freezing embryos so that not all of the healthiest ones had to be transferred to the woman immediately became more popular.

After an earlier study by the Chinese team showed that frozen embryos were better for women with PCOS, "a lot of people jumped to the conclusion that we should always do frozen".

In a Vietnamese study, rates of live births after the first transfer were comparable between groups: 33.8% with frozen embryos and 31.5% with fresh embryos, according to Lan N. Vuong, MD, PhD, of the University of Medicine and Pharmacy at Ho Chi Minh City, and colleagues.

"It's good that [clinicians] will be able to advise patients that frozen-embryo transfer is as good as fresh, because historically frozen has not been as good".

"We shouldn't be freezing embryos across the board [for all IVF cycles] if it makes no difference", says Dr. Christos Coutifaris, president of the American Society for Reproductive Medicine and chief of reproductive endocrinology at University of Pennsylvania, who was also not involved in the study.

For their study, Chen and colleagues enrolled women at 20 clinical sites across China between March 2015 and November 2015.

The study included nearly 800 couples undertaking IVF in Vietnam, who received either fresh or frozen embryo transfers on a randomised basis and was completed in under a year. All women had regular menses and were undergoing their first cycle of IVF or intracytoplasmic sperm injection because of tubal factors, male factors, or both.

It was her frozen embryos that gifted her two daughters, Melissa, now 20 years old, and Ashley, 17.

After the first completed cycle of IVF, ongoing pregnancy occurred in 36% of women in the frozen embryo group, and in 35% of the fresh embryo group. There were no differences observed between treatment groups in mean birth weight or rates of implantation, ongoing pregnancy or overall pregnancy loss. The live birth rate among those with frozen embryos was 49%, compared to 50% among those with fresh embryos.

Research has previously indicated that women who are infertile as a result of PCOS are significantly more likely to have a live birth if they have frozen embryos implanted, but this study suggests this is not the case for women with infertility unrelated to PCOS. But the fact that thawed embryos "produce the same pregnancy rate with less complications should transform the way in-vitro fertilization is practiced", Vuong said. They also implanted, on average, two at a time.

In the other study, led by researchers in China, women at multiple clinics were randomly assigned to receive fresh or frozen embryos.

Legro reported receiving consulting fees from Ogeda, KinDex Pharmaceuticals, Fractyl Laboratories, Bayer, and AbbVie and grant support from Ferring Pharmaceuticals.