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Hello
I was wondering if you could tell me how important an embryo's grading (quality) is. From time to time we see people with lower grade embryos getting pregnant, whilst people with seemingly great quality embryos (that have also been 24 chromosomally tested) are not.
Hello Zibibbogirl,Quote:
Originally Posted by zibibbogirl
That's a great question. The shortest answer is that it is very important, not because it is such a useful tool but because it is the only tool we have currently to judge quality. But it is not a very good tool because beautiful embryos can fail to implant as you note and less than stellar graded embryos can result in pregnancy. If you rule out aneuploidy (chromosomal abnormalities) that rules out the biggest embryo factor for why embryos don't implant. Other factors have to do with the metabolic health of the embryo which is not obvious from the outside. Some embryos may have too few mitochondria (in number or quality) and so literally have less "strength" to divide and multiply since mitochondria are the powerhouses of the cell. Clinical trials are starting to see if stem cell injection of mitochondria from a patients own ovarian stem cells might produce healthier eggs and embryos.
But embryo implantation is not dependent solely on the embryo, the uterus must be receptive to the embryo and assist the embryo in the implantation process and in creating a placenta. Molecular problems at the cellular level in the uterus can interfere with implantation- the right receptors might be absent or not displayed at the right time. Cells deeper in the uterine layers may fail to limit the implantation process, creating a tumor. Large uterine obstructions like fibroids can make the uterus inhospitable to the implanting embryo. Previous D&C's or other surgeries can leave scarring or adhesions, that can also impact implantation. In fact so many things can go wrong, that it sometimes amazes me that we have the human population we have.
The next advance in IVF will be a metabolic or other functional measurement of embryo quality so that among a group of similarly "pretty" embryos , the one with the best implantation potential can be picked out. So right now, we lean heavily on "grades" because that's all we have but researchers are working hard to change that.
More posts
on this topic:
Can ovarian stem cell technology replenish ovarian reserve? | Fertility Lab Insider
Understanding the Gardner blastocyst grading scale | Fertility Lab Insider
The embryo beauty pageant and why your eggs don’t care if you yoga. | Fertility Lab Insider
Thank you Carole, that was very informative.
It is nice to know that once chromosomal abnormality is ruled out and the uterus has had the best possible preparation, that grading isn't a must have in order to be successful. I found the links to those articles to be great reading. Many thanks again.
Very interesting. One thing I have always wondered is: are 'better looking' embryos are more likely to be chromosomally normal? I know that a perfect looking embryo can still be abnormal, but wonder if it is more likely to be normal than, say, one that doesn't look so good.
Hi CrystalTipps,Quote:
Originally Posted by CrystalTipps
It sure would be convenient, wouldn't it? But the correlation between appearance and chromosomal normality is weak at best. Papers have been published to try to identify specific appearance markers that could help us pick out the best embryos but even though there is some correlation, the strongest correlation is maternal age. Younger women have fewer chromosomally abnormal embryos than older women. In fact I remember a paper published years ago where they found increased fragmentation (a negative characteristic when grading appearance) among younger women (who we know have less chromosomal abnormalities). So we can't look to appearance to reliably identify normal embryos. Carole