How Is Egg Quality Determined? Can It Be Improved?
Dr. David H. Barad discusses female egg quality and fertility treatments used by the CHR to improve the quality of eggs.
Title: Egg Quality in IVF
Speaker: Dr. David Barad
Why do fertility centers try to determine egg quality?
Well everybody talks about egg quality, but there is no uniform way of measuring it yet. In fact, one of our embryologists, Emma Lazzaroni, is doing a study to see if we can actually measure the egg quality in an effective way. At the end of the day, egg quality is something we know is there, because we get good embryos. So a high-quality egg gives us a high-quality embryo, and there is a lot of agreement about what constitutes a high-quality embryo: blastameres diving on time, equal cell numbers, low levels of fragmentation. We’ve known that for years.
What we don’t know and what we can’t, in the standardized way, predict, is which egg, when we pull it out, is necessarily going to become that high-quality embryo. We are learning ways of trying to score that. The embryologists, at this point, are looking at eggs in the subjective way that you might go to the store and pick a good tomato or a good peach — a lot of different subjective issues. In the study that Emma is doing, she is trying to quantify those things so we can learn even better how to do that. But it’s all about egg quality, because the egg is the machine, really, that’s in charge of early embryo development.
You can think of the embryos as developing in two stages. The first is the liftoff stage: it’s like the rocket just taking off from Cape Kennedy. The first few divisions through that whole liftoff, that initial development, are completely determined by how good the egg is to begin with. All of the RNA, all of the metabolism that leads to those early divisions that makes it a successful embryo, are already present in the egg. The embryo, after it’s gone through a series of those divisions, does something very magical, but it’s farther down the line: it switches off from that program that is already in the egg, which is actually the mother’s program, into the new program that’s the embryo’s program, and that happens down the line. So the embryo that’s a good genetic conception, that is in a good egg, gets through that first stage and then gets to use its second stage, where it is using its own genes, its own program, and then you can have a successful pregnancy. But even a good genetic program that’s in a poor quality egg will never get to that second stage. They never go through the early divisions that it needs to to get a high-quality egg that has a chance of going on to the later stages. So the first step in embryo development is based on having a good, healthy egg.
What does it mean when a doctor tells you that you have poor quality eggs?
Over the last 10 years, there are two ways the doctor might be making those comments. He may be looking at predictive factors like your hormone test, saying, “Oh, you have a high FSH. You’re probably going to have poor-quality eggs,” or, “You’re 42 years old. You’re probably going to have poor-quality eggs,” or he or she may be responding to what happened in an IVF cycle in which you produced eggs but they became poor quality embryos, and he’s saying, “Well, most likely this is because you have bad eggs.”
In general, what influences egg quality?
Egg quality is dependent on everything that it comes before. So the eggs are sitting there on the shelf all of a woman’s life, and then they’re conditioned and developed through those phases of development that go on for the weeks or few months before they actually enter the menstrual cycle. So a high-quality ovarian environment, a high-quality follicle: all those things lead towards how the egg quality ultimately is, and so the ovary is doing the final production on that egg, and everything you can do to improve the environment in which that’s occurring has the potential of improving it.
It’s one of the differences of our approach here at CHR, which is a recognition of that opportunity, because many places will say that if you have poor egg quality it’s just because they’ve been on the shelf for too long and there’s nothing you can do about it. But now there’s an increasing number of schools of thought, of different ways of trying to influence it, and people have tried using nutrition, people have tried using other forms of hormonal treatments, and we’ve been using androgens. It’s likely that many of these different things may be effective. We haven’t studied those nutritional factors or some other hormones yet. We eventually will, but the issue is that there’s an opportunity to try to make it better, and we have evidence that we can do that to some extent.
Can egg quality be improved?
Somebody who either historically has poor quality eggs, or have predictors that suggest they are going to have poor quality eggs, we believe we can improve that quality. We are never going to make them back into 20-year-olds, we are never going to make them back into the way they were 10 or 15 years earlier. We are just going to make them better. Ultimately, chances of pregnancy in a 42-year-old who is going through this process of trying to improve her quality will never be as good as that that which you might get with a donor egg, but we can improve it so that it’s better than when she came in the door.
What’s the significance of creating a scoring standard for egg quality?
I think it helps the embryologist, because there is probably also an opportunity in the laboratory if you can identify an egg that needs more help. Maybe you can handle it differently in the laboratory, maybe you can approach it differently, use different tools, different culture media. At this point, we don’t know that. But if we can, the first step in developing ways of trying to treat them better, or different techniques, is to identify who needs the help. “
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