Published: Fri, January 12, 2018
Entertaiment | By Paul Elliott

Frozen Embryos Aren't Always Necessary for IVF, New Studies Show

Frozen Embryos Aren't Always Necessary for IVF, New Studies Show

The study, published in The New England Journal of Medicine, investigated nearly 800 women who had infertility not related to polycystic ovarian syndrome (PCOS).

Results from two Asian studies suggest that frozen embryos may be comparable to fresh ones for women having in vitro fertilization (IVF), researchers reported.

Rates of live birth after the first embryo transfer were 34 percent in the frozen embryo group, and 32 percent in the fresh embryo group. "After the first fresh embryo transfer, it will be possible to freeze the remaining embryos and transfer them one by one, which is safe and effective", he said.

"Previous research has shown that women who experience infertility because of PCOS benefit from significantly higher live birth rates from frozen embryos in IVF procedures, but evidence was lacking for this approach in non-PCOS patients", said Professor Ben Mol, from the University of Adelaide.

The process of having babies through a frozen embryo transfer (FET) is swiftly gaining acceptance around the world.

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

The rates of the syndrome in the Chinese study were 0.6 percent with frozen embryos and 2.0 percent with fresh.


Freezing embryos also allows couples to take advantage of genetic testing, which can pick up potentially lethal genetic diseases and guide doctors in deciding which embryos to implant. There were no differences observed between treatment groups in mean birth weight or rates of implantation, ongoing pregnancy or overall pregnancy loss.

"Now these two papers, equally large and done in non-PCOS patients, show that in terms of live birth, which is what we care about, there is no difference", Christos Coutifaris, a doctor at the University of Pennsylvania's Perelman School of Medicine in Philadelphia, told Reuters.

Li Peng Monroe, top left, and her daughters, Melissa, 20, right, and Ashley, 17, front, were conceived using frozen embryos.

Yuhua Shi, M.D., Ph.D., from Shandong Provincial Hospital-Shandong University in Jinan, China, and colleagues randomized 2,157 ovulatory women with infertility who were undergoing their first IVF cycle to undergo fresh-embryo transfer or embryo cryopreservation followed by frozen-embryo transfer.

The shift to frozen embryos was triggered by a landmark study in the field published in 2012, which found that frozen embryos actually were more likely to successfully implant in the uterus when transferred than fresh embryos - and theoretically more likely to result in a full-term pregnancy and live birth. 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.

The study by Chen et al was supported by grants from the National Key Research and Development Program of China, the Major Program of the National Natural Science Foundation of China, and the State Key Program of the National Natural Science Foundation of China.

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