IVF Diary Part 11: Embryo updates

This is Part 11 of the IVF Diary series. I’ll be keeping a diary of all important IVF days, starting from when we first chose to undergo infertility treatment in Prague. Click here to read all other IVF diary posts.

I just wanted to give you a quick update on how the little embryos are doing so far. The clinic updates us every day with how many are still alive, how many cells each of them have, and what grade they are. All embryos have their own unique number so we get to see how each individual embryo is doing.

It’s absolutely great that they’re keeping us in the loop but I do feel nervous every morning before getting the update. I just got the last update, and with tomorrow being a Sunday, I won’t get another one until right before my scheduled transfer.


Embryo Day 1

If you read Part 10 of the diary, you know that we had 13 fertilized embryos on Day 1. There were 23 eggs collected and 5 of those were too small to work with. These are called GV eggs and they’re basically completely useless.

The other 5 that didn’t make it were M1 eggs. M1’s didn’t undergo meiosis and don’t develop properly. People often use the word “mature” or “immature” but a better term for those eggs would be “dysmature” as they can just as easily have been harvested too late instead of too early.

Anyway, those 5 M1 eggs were put out to incubate a couple more hours to see if they’d develop. They didn’t. So they were tossed with the rest of the useless ones.

The other 13 were all M2 (MII) and, using ICSI, all of them fertilized. The fertilization rate is generally around 70%-85% for ICSI, so getting them all fertilized is pretty cool!


Embryo Day 2

Well, all 13 made it to Day 2! Five of them had 4 cells, while 8 of them had 2 cells. All embryos were graded as “1-2” which means that they were of high quality. The grading refers to the size of the cells and the amount of fragmentation seen.

You want the size of all the cells to be as equal as possible, and the fragmentation to be as low as possible. Grading of embryos that contain just a tiny number of cells is hard, and some clinics don’t even bother. The grading goes from 1 to 4 or 1-5 and the higher the number, the more fragmentation/unequalness of cells.

You also don’t want the embryos to grow too slowly or too quickly. They should be between 2 and 4 cells on Day 2. So while 8 were slower to develop, my coordinator assured me that they were still developing as they should.


Embryo Day 3

Today, we got word that all 13 are still alive! Day 3 embryos are also called “cleavage” stage embryos and up until a couple of years ago, this was the most popular day to transfer and freeze the embryos. It still is in some countries.

Now, we know that by cultivating them for an additional two days, we’re able to “weed” out most of the abnormal ones which leads to a significant increase in pregnancy rates. It’s one of the best and easiest selection tools out there.

Seven embryos now have 8 cells and 6 have 6 cells. All are rated as “1-2”. I guess my clinic doesn’t distinguish between 1’s or 2’s? While I’m certainly happy they were rated highly, I don’t put too much value into it as it really isn’t an exact science.

Up until Day 3, the maternal DNA has done the heavy lifting. After, there is an interplay between the maternal and paternal DNA that the embryo is now expressing all by itself. Most embryos (50-70%) die off between Day 3 and Day 5. It’s thought that 90% of those that fail to make it to Day 5, wouldn’t have made it in your own body either. So in a weird way, that’s a little bit reassuring, right?


Embryo development flow chart

We’ll see how many we have left on Monday. I know it won’t be 13, that’s for sure. But I’m keeping my fingers tightly crossed that we’ll at least have a good embryo to transfer! It wouldn’t be the first time couples went from having multiple good quality Day 3 embryos to having none on Day 5.

All we can do now is wait... Which happens to be one of my least favorite things in the world!

Click here to read how the transfer went and how many made it to Day 5.

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  • Kayte

    December 9, 2017 at 3:30 pm

    Catching up on your blog and WOW!! I have never heard of 100% of embryos successfully fertilizing (or as many as 13) AND all surviving (and thriving) to day 3. This is absolutely incredible and I’m so excited for you. The waiting is hard, but you’re off to an outstanding start, and you’re in a beautiful place to help pass your time. xo


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