There are many decisions to make on your journey to becoming a parent. Which infertility clinic is a good fit? What treatments are you willing to undergo? Is it better to transfer fresh or frozen embryos for IVF (In Vitro Fertilization)? Luckily, your treatment team can help guide you to the choices that are right for you, and The Reproductive Care Centre can give you some insight into the pros and cons of fresh versus frozen embryo transfer below.
A Fresh Perspective
All embryos start out fresh. In a woman’s initial IVF cycle, she takes medication to first “quiet” the ovaries followed by medication to stimulate them to produce extra eggs. After the eggs have been surgically retrieved, they are fertilized. The resulting embryos grow in a special incubator until they are ready to be transferred to the uterus. In most cases, one embryo is selected for transfer and the remaining embryos are frozen. Fresh cycles were, for decades, the gold standard…until the last few years when rapid advancements in freezing and cryopreservation methods improved the outcome of FETs.
Back in the Day
First, a little history on frozen embryo transfer (FET). Embryos were initially frozen slowly which caused intracellular ice to form; unfortunately, the ice often damaged the embryos. Many damaged embryos didn’t survive, and those that did had very low potential for successful implantation. However, in the last several years we’ve seen a dramatic increase in the quality of frozen embryos due to the introduction of vitrification. Vitrification is an ultra-rapid freezing method that freezes the embryo approximately 60,000 times faster than the older method of freezing. This process takes ice formation out of the equation, resulting in a significant increase in viable embryos with successful implantation and pregnancy potential equal to fresh embryos.
Timing is Everything
Another reason we see markedly higher FET success rates now than several years ago is that the timing of when the embryo is frozen has changed. It’s been shown that freezing blastocysts (embryo at day 5-6) has a better outcome than freezing early-cleaved embryos (day 2-3). In many cases embryos that don’t successfully develop to the expanded blastocyst stage are aneuploid (chromosomally compromised) and don’t result in healthy babies. An additional benefit of FET using expanded blastocysts is that fewer embryos – because we’re able to determine which are most viable – need to be transferred. This means we can minimize the chance of a multiple pregnancy, along with the inherent risks to both mom and baby.
Fresh or Frozen?
At this point, studies show that successful outcomes using FET are about equal to those of fresh embryo transfers. The slight edge that fresh embryo transfer may have is that, typically, the best embryo is selected for the first transfer. However, there are some key benefits that make FET appealing:
- Because you underwent ovarian stimulation and egg retrieval for your fresh cycle, you won’t have to go through it again. The medications necessary to prepare your body for FET have fewer potential side effects and take less of a toll on your body.
- Many patients report that FET cycles are not nearly as stressful as fresh cycles since they already know they have viable embryos.
- It’s easier to schedule and plan for FET cycles than fresh cycles.
If you’d like to learn more about how fresh and/or frozen embryo transfers and IVF may benefit you, schedule an appointment at The Reproductive Care Centre to meet with a physician and discuss your options.