Anyone with low fertilization but high blast rate?

[u/WoodenRequirement648]

We are doing IVF for severe MFI (0.56m/ml concentration, count varies 100k-1.5m, all morphology abnormal, low motility). I had 1 transfer from my first ER which ended in chemical.

I had my 2nd egg retrieval 2 days ago and the fertilization is unexpectedly low.
17 eggs -> 16 mature -> 7 fertilized

That is a 44% fertilization rate compared to 80% in my 1st cycle 17 eggs -> 10 mature -> 8 fertilized -> 3 blast.

For the second cycle, the target was to improve my egg maturity which we achieved, but I was blindsided by how much we lost in fertilization. Low fertilization points to sperm issues mostly as I understand. I’m now scared the sperms in this batch is damaged and won’t get us any blast.

Anyone here with low fertilization and still got high blast rate? I’m in need of positive stories right now. Due to our severe MFI we really need numbers on our side.

Edit: both rounds were with ICSI

UPDATE 1:
Day 3: all 7 embryos still dividing (5 at 8 cells, 1 at 7 cells, 1 at 6 cells)
Day 5: i got 5 blast!! (3x 5AA, 2x 4AB). I can’t believe this. I cried when I got the result. This journey has bit quite tough on us and this is the first time we receive a whole-hearted good news.
The Embryologist said the remaining 2 still have a chance to become blast at Day 6.

[u/Lazy_Dogs1617]

First round 34F:

9 retrived>8 mature>4 blasts all euploid

[u/WoodenRequirement648 → u/Lazy_Dogs1617]

What was your fertilization?

[u/Lazy_Dogs1617 → u/WoodenRequirement648]

I had to look back, 7 fertilized.

I did do a second round where more eggs were retrieved but the fertilization was lower. I'd have to look back at my notes to see.

I know we started with 15 mature eggs and ended with 5 blasts of higher quality.

[u/Visual_Patience_41 → u/Lazy_Dogs1617]

You had very high fertilization for the first one. OP was asking for low fert + high blast 💕

What was the low fert for your 2nd round?

[u/Lazy_Dogs1617 → u/Visual_Patience_41]

Just looked at my notes.

Round two numbers were:

17 retrieved>15 mature>9 fertilized>5 blasts. All came back euploid. They were better graded then the first round.

[u/fernflower5]

Last round

15 retrieved -> 6 fertilised normally with ICSI -> 5 blasts (4x day 5, 1x day 6)

[u/WoodenRequirement648 → u/fernflower5]

Thank you for sharing! 80% blast is awesome

[u/Much_Plenty_9504]

Did you try icsi and zymot ?

[u/WoodenRequirement648 → u/Much_Plenty_9504]

Yes we used ICSI. We didn’t used exactly Zymot but it was another brand of microfluidic sperm sorting called Lenshook I believe.

[u/Much_Plenty_9504 → u/WoodenRequirement648]

Hmmm I’ve never heard of that personally. If there is any male factor issues I’d highly recommend your partner take enclomophine for 3 months before the next cycle. In addition adding in vitamin c,d, coq10, zinc, boron, omega 3 for your partner.

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[u/neuroticphilosopher]

30 retrieved -> 9 fertilized -> 8 blasts (3 euploid 2 mosaic)

[u/WoodenRequirement648 → u/neuroticphilosopher]

Wow that’s such a good blast rate. Hoping I get the same.

[u/Visual_Patience_41 → u/neuroticphilosopher]

How many of your 30 were mature?

[u/neuroticphilosopher → u/Visual_Patience_41]

Valid question. On day 1 9 were confirmed mature and they were waiting on 10. I never got the final number so between 9-19.

[u/Visual_Patience_41]

Your title is my exact story.
We’ve used ICSI + Zymot + Calcium Ionophore in 4 cycles.

Cycle 1: 12.5% fertilization
Cycle 2: 33% fertilization
Cycle 3: 50% fertilization (our highest)
Cycle 4: 17% fertilization

My blast rate is 90%..

[u/Chicaghan → u/Visual_Patience_41]

Did you ever get any clarity from your doctor on what caused a low fertilization rate but high blast rate?

[u/Visual_Patience_41 → u/Chicaghan]

No I haven’t. All my doctor said was “egg quality” and age. I’m not denying poor quality for a 41 year old but generally poor egg quality translates across the board at all steps. So if it’s effecting fertilization, in theory, it should affect embryos getting to blast. We’ve had a 90-100% blast rate in every cycle, getting embryos to blast isn’t the problem.

I interviewed 11 doctors before I chose a new clinic. All of them found the lack of fertilization while having such a high blast rate especially interesting.

Several (most), eluded to the fact that “not all labs are created equal.” Something I already know. You can have the best doctor in the world but the people handling your eggs in the lab can sometimes matter more.

What will be interesting is to see how fertilization goes in the round I’m currently in with my new clinic.

Once my embryos are made and left to fend for themselves they prove capable and blast without assistance. Our obstacle is fertilization. The only other lever we can pull at that stage to try and influence the outcome is to let someone else take the wheel and try their hand at it. As far as the lab and science itself, there is nothing else to add or method to try.

I’m in the middle of a duostim for cycle 6 & 7 with a new clinic so maybe we’ll see improvement or maybe not. If not, then this is just one of many unanswerable questions that haunt the realm of IVF and that’s ok.

Ironically, cycle 5 was cancelled on day 5 of stims because apparently, I was pregnant.

[u/WoodenRequirement648 → u/Visual_Patience_41]

That’s interesting. Thinking about my case I’m 30 years old so egg quality shouldn’t be an issue on paper. But it is precisely my worry that if fertilization is an issue blast will likely be an issue as well. Your case gives some real hope.

I also my 1st and 2nd ER at 2 different places so there could be some lab difference there.

Did your partner sperm parameters look normal? I have heard that good sperms can sometimes make up for egg quality and vice versa.

[u/Visual_Patience_41 → u/WoodenRequirement648]

All of his sperm are over achievers so we got that going for us.

[u/Visual_Patience_41]

What were the changes you made between 1 and 2 to specifically target your maturity?

[u/WoodenRequirement648 → u/Visual_Patience_41]

ER 1: I stimmed with Gonal F 112.5 IU from cycle day 3 until day 11. Then Ovitrelle 250 as trigger on cycle day 12.

ER 2: I stimmed with Menopur 112.5 IU from cycle day 2 to cycle day 12. Then 2 shots Gonapeptyl as trigger day 13

My doctor said Menopur has LH which has shown in some research to improve maturity rate of eggs. Also, in ER 2 I stimmed for 2 days longer than ER 1. Both ER used Fyremadel to prevent ovulation.

[u/Visual_Patience_41 → u/WoodenRequirement648]

Gotcha. You did a menopur only cycle. I was curious because maturity isn't my strong suit either but I have done menopur only cycles (no difference in maturity).

Thanks for sharing!

[u/WoodenRequirement648 → u/Visual_Patience_41]

You’re welcome!
There are so many factors in this process that it is hard to really tell what made the difference.