How does your clinic grade embryos?

embryoman · September 2018

Hello all! As an embryologist I get a lot of questions about embryos and I want to help as much as I can but sometimes it can be a bit overwhelming! So I thought it would be a good idea to put a blog together to address some of the most commonly asked questions. It will be great because it will (1) make me a better embryologist through research and (2) help everyone out!

My first post will be about embryo grading. I want to make it as comprehensive as possible so I'm reaching out to you guys to help out!

What system does your clinic use to grade embryos and how does it work? What's good, what's bad, etc? If you're not sure, just list the grades of some of your embryos (cleavage/morula/blast) and anything you know about it and maybe I can figure it out. If you don't want to list your actual grades, just make some up in the style your clinic uses.

For example, for cleavage stage embryos a typical grade for my clinic might be 4/8. The first number is the quality (4 is good, 1 is poor) and the second number is the number of cells. For a morula, a typical grade would be 4M (number is quality, 4 is good, 1 is poor; "M" denotes a morula). For blasts, a typical grade would be 3AA. The number is the developmental stage (1,2 = early; 3,4= expanded; 5,6=hatching), the first letter is the quality of the inner cell mass (A=good, C=poor) and the second letter is the quality of the trophectoderm.

Hopefully lots of people can respond so I can make it as complete as possible.

Thank you!

northbeach3 · September 2018

my clinic doesn't give me grade updates for cleavage/morulas, but my clinic uses the 1-6 AA - CC model. I don't know what the lowest grade that they will accept, but have had as early as a 3AA that thawed to a 5BB. my RE has said I have some lower graded ones, and i may have seen some BCs on his chart -- but it was a stretch to see. HAHA

mayflower513 · September 2018

I think ours is 1-5 AA-CC (with AA, AB, BA, BB etc all options). But I guess it could be 1-6. I had 4 and 5AA’s, I know the 4’s weren’t hatching yet but it was considered excellent quality.

wishing-and-hoping · September 2018

my husband took the phone call when they gave the info about our one embryo that made it to blast. all they told him was that it was a grade "B" which they said was average and that's what all the pregnancy/live birth percentages are predicted off of - grade "B" or "average" blastocysts

mbradfo2 · September 2018

1-4 (before hatching) with two letters after -- A being best, C being worst.
Ours were 4BB but started to hatch when they were thawed so if they had been regraded, it would have been a 5 or 6 BB

They did not tell us the grading though since the clinic doesn't feel grades necessarily correlate to success. I only found out after I graduated and they sent my records over to my OB.

I met with our embryologist right before the transfer and he showed me pictures of the thawed embryos and said they looked awesome and we couldn't get better.

mayflower513 · September 2018

This is my sheet if it helps

northbeach3 · September 2018

uhm, so awesome you got the full report @mayflower513! i love reading this kinda stuff!!

callingthestork · September 2018

On day 3, my clinic calls with the number of cells and percent fragmentation (8-cell with 10% fragmentation for instance). On day 7, all they tell me is fair, poor, or good quality blast. I didn't realize 'early' could be a stage of blast, I thought it meant they made a blast sooner! Now I have to ask them about that.

tosh24 · September 2018

My clinic grades according to the Gardner classification system. I had 10 blasts make it to freeze and they ranged from 4AA to 3BC. I know that I transferred a 3BC for my 3rd FET (I had better graded embryos but we wanted to use up our IVF cohort first before using embryos from our ICSI cohort) that was hatching after thaw, but when I asked my RE if they re-graded prior to transfer she said no. I also have a sheet from the lab like mayflower513 but don't know where it is right now. If it would be helpful to you, I can try to find it.

embryoman · September 2018

Thanks guys! Keep them coming!

@mayflower513 awesome thanks! Wow what an improvement between some of your Day 5's and Day 6's. Interesting that your embryos are graded on Day 2 and not Day 3. I'm guessing the CF is for cell fragmentation, S is for symmetry, and M for multinucleation.

@callingthestork Thanks! Do you know what they consider "good" and "poor" for fragmentation on Day 3? Early blast refers to the expansion of the embryo. So a 1AA or 2AA are early. 3&4 are expanding and 5&6 are hatching or hatched.

@tosh24 hanks! No need to get the sheet but I won't stop you if you do! May I ask if you had better success with the ICSI or the IVF cohort?

callingthestork · September 2018

@embryoman, the nurse has said that 10% fragmentation is good, and 25% is bad. No idea where the cut off is. I had an 8-cell with 10% or less fragmentation not make it to freeze, which surprised me. Do fragments always contain DNA, do you think? How much of the material bulk of a cleavage-stage embryo is DNA?
Thanks.

embryoman · September 2018

@callingthestork Was it an 8-cell on day 5 or Day 3? Day 3 is ok but too slow for Day 5. Fragments seem to contain cytoplasm (cellular fluid) and not DNA or organelles. They may be a precursor to apoptotic (suicidal) cells. Each cell of a cleavage stage embryo contains DNA and this is usually restricted to the nucleus. Small messenger RNAs (transcripts from DNA containing messages the cell can interpret to make proteins to serve functions) can exist in the cytoplasm and possibly in fragments.

tosh24 · September 2018

*TW PG/LC mentioned*

@embryoman

In terms of making it to blast, we had greater success with our IVF cohort. I had 22 eggs retrieved (18 mature) so we decided to fertilize some by IVF and some by ICSI to see what the outcome of both methods were. Six were fertilized by IVF and 10 fertilized by ICSI (we had two eggs, one from each group that didn't fertilize at all). We had 5 of the 6 IVF cohort make it to blast, and 5 of the 10 ICSI cohort make it to blast. We had a few better graded embryos in our ICSI cohort compared to the IVF cohort but as I mentioned, we wanted to use our IVF cohort first. My first two FETs I transferred a 4AB and a 3AB which resulted in a BFN and a CP, respectively. My 3rd FET we transferred a 3BC and I am now 25 weeks pregnant from that blast. We never had to use the ICSI blasts. We didn't do PGS (we already have two living children together and my issue this time was thought to be progressing endometriosis) so I don't know the proportion of embryos from each cohort that are normal vs. abnormal. I was 34 at retrieval if you can't see my signature (and hubby 37 with no known issues).

suzycupcake · October 2018

@embryoman This is my clinic's grading chart.

Day 5 Expanded Blastocyst Grade I/Hatching Expanded Blastocyst Grade I (A+)

Day 5 Expanded Blastocyst Grade II (A-)

Day 6 Expanded Blastocyst Grade I or Hatching Expanded Blastocyst Grade I (B+)

Day 5 Blastocyst Grade I (B)

Day 5 Blastocyst Grade II/III(B-)

Day 6 Expanded Blastocyst Grade I(B-)

Day 6 Expanded Blastocyst Grade II(B-)

Day 5 Early Blastocyst Grade I (C+)

Day 5 Early Blastocyst Grade II (C)

Day 6 Blastocyst Grade I (C)

Day 6 Blastocyst Grade II/III (C-/D+)

Day 5 Any Grade III embryo (not recommended)

Day 6 Any Grade III embryo (not recommended)

zamoraspin · October 2018

My clinic uses a scale of 1-5 for day 3 embryos, with 1 being the best. They told me that embryos of grade 1 and 2 are the ones with the highest probability of making it to blastocyst.

My clinic uses the method you described in your OP for blastocysts. I'll use the language they used in their email to me but it looks like the same system: "The number is the expansion score with 1 being very early blastocyst and 6 being completely hatched out of the shell. The first letter is on a scale of A to F and is for the inner cell mass... The second letter is on a scale of A to D and is for the trophectoderm. On both of these scales A is the highest grade."

They also told me that they require an embryo to be at a 5 or 6 to be safely biopsied. Is that common?

embryoman · October 2018

@zamora_spin Thanks for the feedback. Interesting that they give the ICM a grade of A-F while the trophectoderm goes from A-D.

For biopsy we typically assist hatch them on day 3 so the trophectoderm can squeeze out by day 5. This way we're able to biopsy earlier embryos from expansion 3. Even if you were to not assist hatch you can laser a hole and (gently) suction a piece out and I've done this with success multiple times.There's plenty of cells by expansion 3/4 so I don't feel like it's harming the embryo but your clinic may be extra cautious.

embryoman · October 2018

@suzycupcake thanks for taking the time to write that in. Seems a bit confusing! I've attempted to interpret it. Maybe you can let me know if you think this is right?

A+: Day 5, expansion 4-6, grade III (interpretation: Day 5 4AA, 5AA or 6AA)
A-: Day 5, expansion 4-6, grade II (Day 5 4BB, 5BB 6BB)
B+: Day 6, expansion 4-6, grade I (Day 6 4AA, 5AA, 6AA)
B: Day 5, expansion 3, grade I (Day 5 3AA)
B-: Day 5, expansion 3, grade II or III (Day 5 3BB or 3CC), or Day 6, expansion 4, grade I or II (Day 6 4AA or 4BB)
C+: Day 5, expansion 1-2, grade I (Day 5 1AA, 2AA)
C: Day 5, expansion 1-2, grade II (Day 5 1BB, 2BB), or Day 6, expansion 3, grade I (Day 6 3AA)
C-/D+: Day 6, expansion 3, grade II or III (Day 6 3BB, 3CC)

So C-/D+ are the lowest grade, right?

thanks again

suzycupcake · October 2018

@embryoman You're welcome. I honestly have no idea because this is my first cycle of this. I copied and pasted my clinic's chart from what was sent to me by them through an email. My embryologist's report agrees with the chart, only it doesn't mention letter gradings.

suzycupcake · October 2018

@embryoman A+ and B+ matches with grade I. I think you have the grading switched around.

embryoman · October 2018

@suzycupcake oops! you're right, thanks!

embryoman · October 2018

@suzycupcake @zamora_spin @northbeach3 @mayflower513 @wishing-and-hoping @mbradfo2 @callingthestork @tosh24

Hi everyone! I've finally got the post ready on embryo grading. It took quite a bit of effort but I think it's paid off. Thanks to everyone for contributing. I'm hoping this can help people understand a bit more about grading embryos and why good looks don't mean everything. Check it out!

https://www.remembryo.com/embryograding/

tosh24 · October 2018

@embryoman Whoa, now THAT is an excellent and informative blog post! It is obvious how much time and effort went into putting all that information together and I have no doubt that it will help a lot of people understand embryo development and grading and how these may (or may not!) relate to their chances of success. Thank you so much for putting this together! I may be past this point in my journey, but I definitely look forward to your future posts and sharing your blog with others undergoing IVF!

Edited to fix a typo I just noticed!

zamoraspin · October 2018

@embryoman This is awesome! Thanks for putting it together.

embryoman · October 2018

@tosh24 @zamora_spin thank you for the kind words! It was a good time. I'm looking forward to starting the next one. Likely will be on PGS.

babydust2507 · October 2018

I've been lurking this forum, thank you @embryoman good info!

jazziep · October 2018

It sounds like others received a lot more information than we did about our embryos.
The embryologist simply told us that out of the 5 we had (blast) one was a 4, which she said is a higher grade, two were 2s, two were 1s.

Our 1s didn't survive to cryo 😥

embryoman · October 2018

@babydust2507 thanks!
@jazziep Some clinics only like to report the expansion (size) of the embryo. They find that this works best for them. For our clinic, the cut for our clinic are 3's (sometimes 2's). Embryos with an expansion of 1 sometimes don't make it any further

babydust2507 · October 2018

hi @embryoman i just had my FET this morning and they transferred a 4B+A. i'm just curious to know how you would have graded it, if you don't mind

Image: https://us.v-cdn.net/5020794/uploads/editor/a6/ytmlpb7k8jps.jpg

embryoman · October 2018

@babydust2507 hard to say since it's not completely expanded (they're collapsed when frozen and take some time to re-expand after thaw). Also the "+" in your clinic's grading is a bit odd for me but I could see how that might be a 4BA. When embryos are completely expanded before freezing, that's when grading is best performed. Good luck!!

babydust2507 · October 2018

thank you @embryoman for your insight, I really appreciate it!

Tulips29 · February 2019

Hi @embryoman. I just received my PGS results and have 1 embryo that's graded 4BB and 1 that's 1-2B-B-/C, 5ins. Clinic is telling me both are good enough to transfer by the 4BB has about a 60% chance of implantation and the other one about 20% chance. I've never seen a grade such as 1-2B-B-/C, 5ins. Any insight into what it all means?

Image: https://us.v-cdn.net/5020794/uploads/editor/ea/esk3q1652pat.png

somewhereinnyc · February 2019

@Tulips29 you’re at Cornell too right? They’ve got a modified grading system I think. I’m sure it’s somewhat subjective.. pgs results might have more weight? i think the C grade is for the trophoectoderm that forms the placenta on that embryo.. not the inner cell mass/ baby. At least you got to keep your C blastocyst I suppose. I apparently had a C blastocyst but they decided not to freeze it.

Tulips29 · February 2019

@somewhereinnyc Yes, I'm at Cornell also. Did they tell you why they didn't keep the C embryo? I'm really confused on this grading, especially the "1-2-b-b-/c, 5ins". No clue what that means but my doc referred to it as a 1BB embryo.

cashewchicken · February 2019

@Tulips29 My clinic grades the embryos on A-D for Inner cell mass and Trophectoderm instead of the typical A-C grading. I was told that at my clinic they will transfer embryos with better than C grade. The poor quality embryos have lower chances of success but as long as they’re euploid, you shouldn’t count them out!

somewhereinnyc · February 2019

@Tulips29 no, they did not tell me why they decided not to freeze it. Maybe it just wasn’t good looking enough? Maybe not all C’s are the same? They did transfer 1 and freeze 5.. but the ones they decided to freeze are al A- or B in grade. I also didn’t do PGS.. not sure if that changes anything. It is confusing and stressfully but I guess we can’t change them. Are you deciding whether to bank more or transfer? Or just trying to understand?

Tulips29 · February 2019

@somewhereinnyc It is really confusing. I also didn't ask if my embryos are euploid or not. I'm doing another retrieval before proceeding with a transfer. Hoping for a better outcome next month!

cashewchicken · February 2019

@Tulips29 Euploid embryos are normal embryos. Based on your earlier post, the 1BB embryo is euploid, if your RE said they were normal and can be transferred. Hope your 3rd ER is successful and result in all the normal embryos that you want! I went through 3 RE myself and I know how hard it is. I’m doing a FET later this year.

murph145 · February 2019

@cashewchicken the only way you know if the embryo is euploid is if it has gone through genetic testing..... the grading that clinics do only grades the physical aspects of the embryo..... if you don't do genetic testing you don't know if your transferring a healthy euploid embryo or not.

All I can say once again is that the older you are the more helpful the pgd testing is. Also its recommended for couples that have multiple MC as its probably due to chromosomal issues

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