Are Frozen or Fresh Embryos Better for Fertility?

Pregnant woman holding baby shoes

The Society for Assisted Reproductive Technology has noted that more fertility centers choose to use the frozen embryo method. Experts believe this is the first time a significant experiment was performed to evaluate this change of practice.

Many women who are struggling to conceive consider turning to in-vitro fertilization to improve their chances. But which type of embryo transfer will give you a better probability of pregnancy – frozen or fresh?  

This decision may provoke even more feelings of uncertainty or nervousness, but worry no longer! A recent study completed by researcher Heping Zhang at the Yale School of Public Health discovered there is an insignificant difference in live birth rates between the two procedures.

The study was published in the New England Journal of Medicine.

Heping Zhang collaborated with a number of scientists throughout China, and together, they observed 2,157 women who were going through their first in-vitro fertilization cycle. Each woman was randomly assigned either fresh or frozen embryos.

The research team discovered that the frozen embryo group had a live birth rate of 48.7 percent compared to a 50.2 percent for the women who had fresh embryos. There were no significant differences between the two groups in terms of implantation, clinical pregnancy, pregnancy loss, and ongoing pregnancy.

However, the study did show that frozen-embryo transfers resulted in a much lower risk of ovarian hyperstimulation syndrome (OHSS) – which is when your ovaries become swollen and painful – than the fresh-embryo transfers. Most cases of OHSS are minor, but severe cases can end in illness or in especially rare instances, death. The women who used frozen embryos had a 0.6 percent chance of developing OHSS, while the women who used fresh had a 2 percent chance.

Zhang commented, “This is an emerging issue of immediate and important concern for couples who are seeking in-vitro fertilization treatment.”

Zhang says the research findings will impact patients and doctors, who may approach their evaluation and consideration of embryo transfer differently, now better able to calculate the risks and benefits. He also said the studies exemplify “the success of a multidisciplinary and international collaboration in addressing emerging and clinically important issues that patients and clinicians face as the technologies quickly evolve.”

If you are still wondering which fertilization process would be best for you, don’t hesitate to consult a specialist.