[In Vitro Fertilization] Is it correct to transfer the best blastocysts first? | P-11

Recent flow:
(7) Egg retrieval cycle ① Clomid method
(8) Egg retrieval cycle ② Clomid + rFSH method
(9) Fertilization method and results
(10) Correlation between early embryo and blastocyst evaluation

Up to the previous post, we reached egg retrieval → fertilization → blastocyst freezing, and before finally moving on to the transfer cycle, I have summarized what I researched and what I thought.

Reviewing embryo transfer

Fresh embryo transfer and frozen embryo transfer

In in vitro fertilization, the "fertilized egg" that has been successfully retrieved and fertilized is:

(A) Fresh embryo transfer
Returned to the uterus in the same cycle

(B) Frozen embryo transfer
The early embryo or blastocyst is frozen and returned to the uterus in a subsequent cycle

…one of these methods is used.

In the past, "fresh embryo transfer" was common, but due to advances in freezing technology, "frozen embryo transfer" seems to have become the majority.

This is because the hormonal conditions for egg retrieval differ from the hormonal conditions for implantation and pregnancy maintenance after transfer, and it is easier to obtain good results if the body's "egg retrieval mode" is reset before proceeding to transfer.

However, there are cases where a patient had negative results no matter how many times they tried with frozen embryo transfer, but then had a positive result with fresh embryo transfer, so it cannot be said that frozen embryo transfer is a more advanced method.

Natural cycle and hormone replacement cycle

Furthermore, (whether fresh or frozen,) there are two main ways to return the embryo to the uterus.

(1) Natural cycle
・Allow ovulation and secrete progesterone.
・The clinic visit schedule changes as needed depending on the growth of the follicles.
・Once the follicles grow, trigger ovulation with an hCG injection, and transfer on the 5th day from there.

(2) Hormone replacement cycle
・Do not allow ovulation, and supplement progesterone with medication.
・It is easy to set a fixed schedule.
・Supplement estrogen from the 2nd day of menstruation,
　supplement progesterone from the 14th-15th day, and transfer on the 5th day from there.
・Due to the action of estrogen, FSH is suppressed, making it difficult for follicles to grow (so ovulation should not occur, but it is not absolute.)

Neither is superior to the other, but due to the ease of schedule management, it seemed that (2) hormone replacement cycle is often selected .

* I have also summarized the overall basic matters in the following article, so please take a look if you like.

Also, I think this external link will be helpful.

Which blastocyst should be thawed?

Blastocyst growth report

Now, we have frozen multiple blastocysts and as we prepare to proceed with embryo transfer,

“Which blastocyst should we use?”

is something that weighs on our minds.

For the frozen blastocysts,

・Grades such as “4AA” or “3AB”
・Growth records from the early embryo stage

are written down and listed with photos, and now that we have spent the time and effort to reach the point of freezing several blastocysts, it would be a lie to say that we don't feel a sense of life or individuality in each one.

I think that if we had been able to retrieve dozens of eggs and had many frozen embryos, or if we hadn't experienced IVF and hadn't been conscious of the blastocyst stage in the first place, we wouldn't have worried about this at all.

And this becomes a long-term concern, even after a successful pregnancy and childbirth, in the form of how long should we continue to store the remaining embryos?.

Reference external link:

The first one to be transferred is “4AA-chan”

Now, at the clinic we were under the care of, which embryo to use was left up to the clinic, and basically, we would use the ones with the highest grade first.

In our case, the first batter was a grade “4AA” blastocyst, and we would encourage it by saying
“Good luck, 4AA-chan”
“You can do it,”
and we called it “4AA-chan” throughout that cycle.

The “goal” of fertility treatment (assisted reproductive technology) is to achieve pregnancy and childbirth, not to uncover and cure the root cause of infertility... or so it is said.

Therefore, using the “best-performing blastocyst” for the first turn is a rational choice.

Is it okay to start with the “best-performing blastocyst”?

There are also abnormalities discovered during treatment

Now, when undergoing fertility treatment or assisted reproductive technology,

“Let's try this next, and if it doesn't work, let's do the XX test.”

...there are many such things.

For example...

1. Tried timed intercourse and did not get pregnant,
and upon investigation, it turned out to be male infertility requiring surgery for a varicocele.

2. Tried artificial insemination and did not get pregnant,
and as a result, there was a fertilization disorder,
meaning it was a condition where fertilization was only possible through intracytoplasmic sperm injection (ICSI).

...and things like that.

This is the kind of situation where you think, "If I had known sooner, I would have stepped up instead of dragging it out..."
and it happens.

Embryo transfer is not the final step

Even in in vitro fertilization, when egg retrieval and fertilization go well,
there is a sense of accomplishment like "Oh, I've made it this far,"
and

"All that's left is the transfer..."
and one tends to feel like it is the final step, but...

Even after the transfer, there are several checkpoints such as "whether it grows beyond the blastocyst stage," "whether it implants," and "whether the pregnancy continues."

It is frustrating when you transfer the best-graded blastocysts in order several times without getting pregnant, and then find the cause after additional testing, only to realize there are no frozen blastocysts left...
...

And what about the human rights of the blastocysts that end up serving as, so to speak, test subjects where you try one, and if it fails, you do such-and-such test??

* Blastocysts do not have "human rights" in medical or civil law terms, so there is no need to worry excessively.

You can investigate the factors in advance, but...

In most cases, if negative results continue even after changing the transfer method (natural cycle or hormone replacement cycle), we narrow down the causes and address them by examining the blastocyst chromosomes through Preimplantation Genetic Testing (PGT-A) or by checking the "window of implantation" through an Endometrial Receptivity Analysis (ERA).

However, setting aside the ethical and emotional aspects of the blastocyst human rights issue mentioned earlier, when considering the physical and mental burden of egg retrieval, it is a bit difficult to accept the approach of

"Let's try it, and if it doesn't work, let's do such-and-such test."
proceeding in that manner.

A tricky point when performing tests like PGT-A or ERA is the issue that
the combination of "self-funded testing and insurance-covered (30% co-pay) egg retrieval/transfer" is not permitted, and everything becomes self-funded
..., and in that case, there are instances where "the total cost for egg retrieval, freezing, transfer, and PGT-A exceeds 1 million yen."

Regarding this, there are movements toward expanding insurance coverage, such as PGT-A being classified as "Advanced Medical B" starting in 2024, but it seems there is still a long way to go...

Summary

This time, I wrote down my thoughts on the point of "which frozen blastocyst to thaw" as we proceed to the in vitro fertilization transfer cycle.

To put it in modern terms,
・Time performance (how quickly to get pregnant)
・Cost performance (wanting to stay within the limits of insurance coverage)
・Mental performance (it is mentally tough to repeat negative results)
Since these cannot all be achieved at the same time, I think this is why struggles arise in deciding how to proceed with treatment.

Next time, I will introduce the first transfer cycle (hormone replacement cycle).

Guide to the Pregnancy and Childbirth Series
・Next article P-12 In Vitro Fertilization Transfer Cycle ①
・Previous article P-10 Correlation between "cleavage stage embryo" and "blastocyst" evaluation

・Please also make use of the table of contents!