Biopsy and Fertilisation Question :)

Hi Carole,

I just have a couple of questions if you don't mind.

In my last cycle (cycle 3), I opted for day 5 PCR (3 probe) instead of day 3 FISH (5 probe) I had previously used, as I was told that the day 5 testing would be more accurate.

I assumed that they would test day 5 on blast, but actually they will only test on Hatching Blasts and will wait up till day 6 to do so. I was told they believe that this is a healthier way to biopsy the embryo. This was at Superior ART in Thailand, but they follow the exact same practice as Genea (Sydney IVF) in Australia. They do do assisted hatching on the embryo to help it get to blast.

My question is, is this normal practice? On this site most day 5 testing is done as long as it is a blast, regardless of whether it is hatching or not. Or is there a move to do day 5 testing on a HB? Is it an individual clinic thing. Would most embryos that are going to test normal make it to HB anyway? Or could we potentially be throwing away embryos that could make a pregnancy.

As it was I only had 2 embryos fertilise and one of these actually made it to HB (which was actually abnormal anyway), so on that my stats were OK. The one that didn't get biopsied was an early blast, grade 3 on day 6.

Finally, how normal is it that not all of my eggs fertilise. My first cycle we spoke about, they used IVF and I had zero fertilisation, after that though they used ICSI and I had average 65% fertilisation. Would this be anything to worry about, or could there be a sperm (or egg) issue?

Sorry for bombarding you :)

Glory

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Originally Posted by glory

Hi Carole,

I just have a couple of questions if you don't mind.

In my last cycle (cycle 3), I opted for day 5 PCR (3 probe) instead of day 3 FISH (5 probe) I had previously used, as I was told that the day 5 testing would be more accurate.

I assumed that they would test day 5 on blast, but actually they will only test on Hatching Blasts and will wait up till day 6 to do so. I was told they believe that this is a healthier way to biopsy the embryo. This was at Superior ART in Thailand, but they follow the exact same practice as Genea (Sydney IVF) in Australia. They do do assisted hatching on the embryo to help it get to blast.

My question is, is this normal practice? On this site most day 5 testing is done as long as it is a blast, regardless of whether it is hatching or not. Or is there a move to do day 5 testing on a HB? Is it an individual clinic thing. Would most embryos that are going to test normal make it to HB anyway? Or could we potentially be throwing away embryos that could make a pregnancy.

As it was I only had 2 embryos fertilise and one of these actually made it to HB (which was actually abnormal anyway), so on that my stats were OK. The one that didn't get biopsied was an early blast, grade 3 on day 6.

Finally, how normal is it that not all of my eggs fertilise. My first cycle we spoke about, they used IVF and I had zero fertilisation, after that though they used ICSI and I had average 65% fertilisation. Would this be anything to worry about, or could there be a sperm (or egg) issue?

Sorry for bombarding you :)

Glory

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Hi Glory,

I will try to answer your questions:
Is this normal practice? Yes, but it is not the only way to do it. In order to have a trophectoderm part of the embryo to biopsy, the embryo must get to blastocyst stage, but the hatching requirement is optional. Some of the biopsy training classes recommend waiting for hatching so that the embryo is already hanging out of the zona and so is easier for the tech to grab and cut off a piece of trophectoderm without having to perform hatching which is another layer of technical skill, particularly if a laser is not available for hatching. But I know really good techs who laser themselves an opening, pull out the trophectoderm end of the embryo and go to work so that all their embryos can be biopsied on day 5 so you don't keep them in culture longer than necessary. I don't have any data to suggest that biopsy on day 6 is necessarily bad. Day 6 blasts produce pregnancies but day 6 transfer preg rates are typically a little lower than day 5 transfer preg rates. In addition, if you have elected to have a day 5 biopsy, overnight test result and transfer of normal embryos on day 6, if your clinic waits until day 6 for hatching, those embryos won't be biopsied in time for a fresh transfer. You'll only have those biopsied on day 5 for which test results are available to choose from for a transfer on day 6.

I see no reason for your program to throw away any day 6 hatching blasts. They should biopsied and frozen, pending test results.

It is normal not to have all your eggs fertilize, even with ICSI, because just getting the sperm into the egg is not all that happens for fertilization. The sperm must open up it's sperm head and let the DNA out (decondensation) and both egg and sperm must create a membrane enclosed sac of DNA called a pronucleus which must combine to mingle the genetics and achieve fertilization. So although getting the sperm is essential, ICSI does not guarantee 100% fertilization. I have a couple of posts discussing this on my blog. Either sperm or egg issues could contribute to zero fert even after ICSI.

IVF Disasters: No Fertilization | Fertility Lab Insider
Egg Count Mathematics: Why the numbers change between retrieval and transfer. | Fertility Lab Insider

There is a search box on the left side of my blog page which allows the reader to enter search terms to find specific topics of interest on the blog.

Hope this helps, Good Luck. Carole

Thank you so much for getting back to me so quick. I am going off to read up on your blogs, but it is reassuring to know that ICSI doesn't necessarily mean there has to be 100% fertilisation.

With the blasts, because it is 3 probe, they have testing concluded for fresh transfer within a couple of hours, so no need to freeze. They will not throw out HB's on day 6, but they will discard unhatched blasts. With Genea, CGH testing requires a freeze on any blasts as results take a few weeks.

I suppose more is the question, would disposing of the unhatched blasts be chucking away potentially good embryos just because of protocol?

Quote:

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Originally Posted by glory

Thank you so much for getting back to me so quick. I am going off to read up on your blogs, but it is reassuring to know that ICSI doesn't necessarily mean there has to be 100% fertilisation.

With the blasts, because it is 3 probe, they have testing concluded for fresh transfer within a couple of hours, so no need to freeze. They will not throw out HB's on day 6, but they will discard unhatched blasts. With Genea, CGH testing requires a freeze on any blasts as results take a few weeks.

I suppose more is the question, would disposing of the unhatched blasts be chucking away potentially good embryos just because of protocol?

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Hi Glory,

It is hard for me to answer that question. If the techs don't have the skill to biopsy an unhatched blast, it boils down to the question of would you transfer an unbiopsied, untested day 6 embryo? If they can't biopsy it and you can't use it without test results, then it is not any good for you. The fact that it is still not hatching on day 6 could point to a problem with the blast but not always. Sometimes blasts expand and then collapse, delaying the progression to hatching. But based on their experience with their culture system, they must have reason to believe that failure to hatch on day 6 makes the embryo non-viable and so discard these embryos. It's a tough call sometimes when to call it quits on an embryo. If we are too lenient and give every embryo a chance, success rates tend to fall. If we are too strict, we risk throwing out an embryo that might have implanted. It's not always clear cut. Carole

Thanks Carole,

Makes a lot of sense. Basically I just have to trust the lab is doing their thing the best for my embryos, harder said than done, I am such an over thinker lol. I don't doubt their skill though, more their preference for HB over blast testing but I understand why now that they would choose this.