If you are considering undergoing IVF treatments, it is possible you have been hearing some conflicting rumors about which process you should use and what’s most successful. For decades, since experts began working with assisted reproductive technology, fresh embryo transfers appeared to consistently have a higher success rate than frozen ones (FETS).
In the past, embryos were frozen because the strongest embryos in the freshly fertilized batch were used first, the rest frozen and reserved for future treatments in case the first ones didn’t take. The process of starting with fresh transfers and preserving “back-ups” as frozen embryos is still utilized at most fertility practices. However, newer technology and analysis has shown that the benefits to using frozen embryos may, in some cases, be safer and more dependable.
Naturally, people are starting to wonder why this would be and which advice they should be trusting. So when considering fresh versus frozen embryo transfer for IVF, which is better?
Fresh Cycle: Pros
- In fresh cycle you are given hormones to stimulate your embryo production which enhances the probability that they will be usable.
- The embryos that have responded the best are the ones chosen to be immediately planted in the uterus.
- This is a technology used for many years with high success rates.
- If this process proves successful for you, you do not have to go through additional hormone treatments and the stress on your body is minimal.
Frozen Cycle: Pros
- When you are transferring FETS your body has had time to return back to it’s normal state. This potentially provides a more natural environment for the embryos, as the “uterine environment is prepared with natural estrogen and progesterone’’ and has been suggested to lead to healthier pregnancies.
- There are less potential side effects.
- You are less prone to emotional stress since the egg production has already been taken care of and the issue of usable embryos resolved.
- You can plan the date of the transfer based on your own schedule as the timing of implantation is no longer a necessity.
- Freezing the embryos keeps them from aging, so your chances are about the same as when they were first frozen.
What to Consider
The frozen cycle does require less of your body and less money out of your pocket at the time of the transfer, but don’t forget you can’t have frozen embryos without initially getting the ovarian stimulation and embryo development (unless you are using a donor egg). If this is your first go at IVF you will still need to go through the same steps it takes to get the fresh embryos, but it is up to you to decide when you want them to be transferred.
Studies conflict on differences in the two processes with regard to important variables. For example, some studies supporting frozen embryos favor women between the ages of 35 and 42. These women chose to freeze their eggs when they were younger, therefore the eggs took to their bodies more successfully than if they had gone through the process of extracting and fertilizing them at their current age.
Other results highlight that in a fresh cycle process the uterine lining is exposed to unnaturally high levels of estrogen and progesterone which could interfere with the fertilization process.
Furthermore, some ‘ovarian hyperstimulation' commonly occurs after receiving hormone treatments and using fresh embryos. This ovarian hyperstimulation syndrome tends to go away very quickly, yet in a few cases has become more severe with serious consequences. Still another consideration was highlighted by the Colorado Center for Reproductive Medicine where they found a “2.8 percent miscarriage rate following CCS with a frozen transfer compared to 18.5 percent in the fresh transfer group.”
Making Your Decision
When looking at all of the collected information you may think that freezing your embryos would be the way to go. The use of donor eggs, especially in the cases of women with certain fertility issues or advanced age, may be encouraged to avoid factors listed above. While freezing your embryos and waiting to transfer for them may improve your outcome over the fresh cycle option, nothing has been officially proven to be statistically significant and it appears to depend on the individual and their unique situation. In order to make your decision, talk to your doctors and fertility experts and consider all of the steps carefully.