Fertility Blog

“Freeze All” Embryo Freezing

Frozen Embryo Transfers (FET)

As the temperature drops, it reminds us to post about one of the issues many of our patients have questions about—frozen embryo transfers (FET). Specifically, we’re discussing “freeze-all” cycles.

A frozen embryo transfer means going through an IVF cycle and creating embryos, but holding the transfer of any of the embryos until a later date. There are many reasons why a patient may choose to do a “freeze-all,” including:

  • Fertility preservation for age or cancer
  • Planned preimplantation genetic testing
  • Desire to have transfer at a later time

Also, something may come up during the IVF cycle that may lower the chance of getting pregnant if a fresh embryo transfer happens, including:

  • Rise in progesterone level near the end of the IVF stimulation
  • Discovery of a polyp or hydrosalpinx
  • High estradiol or risk of ovarian hyperstimulation syndrome (OHSS)


Years ago, the chance of getting pregnant after a FET was lower. However, labs are now freezing embryos with a technique called vitrification and the quality of the embryos is better. In fact, some risks – the chance of ectopic pregnancy or having a baby with low birth weight- are less likely with an FET. In some situations, for some patients, the chance of getting pregnant is better with a FET. However, for other patients, studies tell us that a fresh transfer increases the likelihood of pregnancy compared to a FET.

Fresh vs. Frozen Embryos

Should everyone be doing “freeze-all” cycles and FETs? For now, the answer is no. Studies are still coming out about who may benefit from a “freeze-all” or a fresh transfer. At ORM, we always take your individual situation into account when we decide to recommend a FET or frozen transfer, in turn, giving you the best chance of having a baby.

Dr. Brooke Rossi