Embryo transfer preparation – what can we do to support the process?

When preparing for something like an embryo transfer it’s more than normal to feel apprehensive about the IVF process. Maybe you’re wondering what precautions to take after embryo transfer, what the IVF success rates are with fresh vs frozen embryos or simply what the process is. With this in mind, we’ve teamed up with expert Embryologist Kristen in Australia, creator of the I like my eggs fertilised IVF blog, @ilikemyeggsfertilised, to demystify the process and tell us how we can best go about embryo transfer preparation. Catch our brilliant podcast collab with Kristen, while you’re here.

I personally even wanted to know if there were specific things I should be doing the night before my frozen embryo transfer and what I should be eating the day of my embryo transfer!

Before you read

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Written by @ilikemyeggsfertilised

Your top questions answered, with I Like My Eggs Fertilised

Going through fertility treatment is stressful and overwhelming; but I hope it is comforting to know that there are some topics of concern which are incredibly common amongst patients. These are topics that I get asked about regularly.

Day 3 Vs Day 5

How Many Day 3 Embryos Make it to Blastocyst?

This is an area which will vary greatly amongst patients and even from cycle to cycle. Typically speaking, 40-50% of fertilised eggs will make it to blastocyst, however I have definitely seen patients get much more than this and some patients will struggle to get any at all. Say, for example, a patient gets 10 eggs collected and 8 fertilise, it would be common to see 4 to 6 good quality embryos on Day 3 and of those 2 to 3 make it to blastocyst stage. A lot of people may be upset to ‘only get 3 blasts’, but in reality, this is a great result and people shouldn’t get hung up on what percentage of fertilised eggs make it to blastocyst.

So, as you can see, it’s very common to see a big drop in embryo numbers from Day 3 to Day 5, and it is a common complaint that people may have embryos doing well until Day 3 and then they either arrest (stop developing) or develop very poorly. The reason behind this is that maternal genes are enough to get the embryo to Day 3 and, after this point, the embryonic genes need to activate or be expressed for the embryo to develop further; and this is a common point of deterioration of embryo quality.

Thaw Survival

Over 90% of embryos should survive the freezing and thawing process. When embryos are frozen using the old technique of ‘slow freezing’, the survival is a bit less, but with the current method of ‘vitrification’ that a lot of laboratories use, embryos are frozen at a much faster rate to minimise ice crystal formation, which is a cause of damage to the embryos. These survival rates apply to both Day 3 and Day 5 embryos.

I often get asked about Day 3 to Day 5 embryo survival rates…

Speaking of Day 3 versus Day 5, you may be wondering if one is better than the other. Statistically, IVF success. rates are comparable but it’s up to your individual cycle and circumstances to determine what is best for you. Many fertility clinics now strive for blastocyst culture only and you won’t need to worry about it as the decision is already made for you. For the clinics that offer both, they are likely to aim for blastocyst transfer where possible and alter the plan based on how your embryos are doing. No one can dispute the fact that a woman’s uterus (womb) is a better incubator than an artificial one in the fertility clinic lab and some embryos may do better being transferred earlier on Day 3. Your fertility specialists may opt for this when embryo numbers are low, to give you the best chance of having something to transfer and to give one of those few embryos a better chance with natural incubation. Especially because it can be hard to know how many embryos make it to day 5. However, when multiple embryos are thriving, extended culture to Day 5 will naturally de-select those that are unable to make it to Day 5. Therefore, hopefully this leads to a batch (sometimes smaller) of high quality embryos with a great chance of a successful IVF outcome.

Does Transfer of Two Embryos Increase Chance of Pregnancy?

It is common for patients to think that the more embryos transferred, the greater the chance of pregnancy and many wonder the pros and cons of transferring two embryos. However, a greater chance of pregnancy with two embryos has been proven not to be the case. The chance of a twin pregnancy does increase but not the chance of a regular singleton pregnancy; and as a twin pregnancy is high risk, fertility specialists will want to try to avoid this.

There are multiple factors that determine whether or not your embryo transfer will be successful and, if something is out of line to cause your cycle to fail, you would have lost two embryos instead of one. Depending on your circumstances, your fertility specialist will decide whether they think a single or double embryo transfer would be more appropriate for you. As only a small portion of your embryos are actually genetically normal, you increase the chance of a normal embryo being affected by an abnormal embryo that may lead to baby loss. I have also seen cases where one embryo has implanted in a fallopian tube and the other has implanted in the uterus and both ended up being lost.

Tips For Optimising Embryo Transfer Success

The embryo transfer is a very important part of an IVF cycle; everything you have gone through in the previous weeks (possibly months) before, have all led up to this moment. You will be given instructions from your team, so ensure you follow these correctly as different doctors have different requirements. They can be general or specifically around the day or night before, and more granular embryo transfer preparation guidance.

For example, if your doctor is using ultrasound, you will likely need a full bladder, and they may give instructions about the medications you are taking.

Embryo transfer preparation – on the day:

• Have a shower before your procedure
• You may be asked to miss your morning progesterone pessary (if you take one) and take it after the transfer
• Do not wear strong perfume or deodorant as these put VOCs (volatile organic compounds) into the air which are harmful for embryos. It won’t affect your embryo that is going to be transferred but it will affect air quality in the laboratory
• You may return to work if you need to, or you may want to take the day off to rest. Do not be concerned about your embryo falling out, it is snug in your uterus.