IVF's Numbers Game: The Journey from Eggs to Blastocysts

Welcome back to another engaging episode of "Taco Bout Fertility Tuesday" with your host, Dr. Mark Amols. This week, we delve into the complex and often misunderstood stages of IVF, focusing on the journey from egg retrieval to the development of blastocysts. It’s a numbers game where the stats don’t always add up as expected, and understanding these dynamics can be crucial for anyone embarking on or considering IVF.

In this detailed exploration, Dr. Amols explains the attrition rates at each critical phase of IVF: from the number of eggs retrieved to those that fertilize, and further to those that reach the pivotal blastocyst stage. Why do some eggs fail to fertilize, and what happens to those that do but don't progress? These questions and more are addressed with clarity and insight.

Listeners will gain a realistic perspective of IVF, tempered with both scientific data and personal stories that illustrate the emotional and physical journey involved. Dr. Amols uses compelling analogies, like a disappointing meal at a favorite restaurant, to highlight how expectations can differ vastly from reality. This approach not only simplifies complex biological processes but also connects emotionally with listeners' own experiences.

Whether you’re knee-deep in fertility treatments or simply curious about how IVF works behind the scenes, this episode promises to enlighten and inform. Get ready to adjust your expectations, understand the odds, and learn how the quality of eggs and sperm, technological interventions, and personal health all play integral roles in the success of IVF treatments.

So grab your favorite taco and settle in for a session that demystifies the numbers and enriches your understanding of the IVF process. It's more than just science; it's about setting the stage for future miracles in fertility treatments.

Thanks for tuning in to another episode of 'Taco Bout Fertility Tuesday' with Dr. Mark Amols. If you found this episode insightful, please share it with friends and family who might benefit from our discussion. Remember, your feedback is invaluable to us – leave us a review on Apple Podcasts, Spotify, or your preferred listening platform.

Stay connected with us for updates and fertility tips – follow us on Facebook. For more resources and information, visit our website at www.NewDirectionFertility.com.

Have a question or a topic you'd like us to cover? We'd love to hear from you! Reach out to us at TBFT@NewDirectionFertility.com.

Join us next Tuesday for more discussions on fertility, where we blend medical expertise with a touch of humor to make complex topics accessible and engaging. Until then, keep the conversation going and remember: understanding your fertility is a journey we're on together.

Transcript

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Today we talk about attrition rate, the journey from eggs to blastocyst. I'm, Doctor Mark Amos, and this is taco. About fertility Tuesday. This is actually a really good follow up episode to last week's episode. Last week's episode was talking about how to determine how many embryos you'll have at the end of a cycle, and going backwards to determine how many eggs you need to start with if you want to have selective insemination. In this week's episode, we're going to. Talk about the attrition rate and what. To expect with the number of eggs you start with and how many embryos to be expecting. See, in life, we get disappointed when. Expectations are not met. And so the point of this podcast. Is to help those expectations, because I'll. Give you an example. I was at Denny's, and I love. Denny's moons over Miami. Hammy. It's one of my favorite breakfast sandwiches. But when I was in flagstaff and I got the moons over Miami, I. Couldn'T believe what I got. It only had, one piece of cheese on a little bit of ham, where normally it has two pieces of cheeses and all this other stuff. And I was, I was sad. I thought, what is going on here? What created this sandwich so much different than before? Well, the same thing happens with IVF. Most people assume that they're going to start with 20 eggs and they're probably going to get 20 embryos, but in. Reality, that is not true. Matter of fact, most of the time. The average number of eggs is somewhere. Between eight and twelve, and the average. Number of embryos at the end is between one and four. And there's a reason why that number drops over time. And so what we're going to do is talk about that process and talk about why the drop is there and what factors could potentially affect that drop even more. So sit back, grab a taco, and get ready to talk about attrition rates. So, for those of you who are maybe just jumping into this podcast and haven't listened to prior podcasts, lets first. Discuss what happens in the IVF cycle. So what happens is when were usually on the birth control to prime their. Ovaries to get ready for IVF, and that synchronizes the eggs so theyre ready to eventually grow. And when we talk about growing more. Eggs, what were talking about is growing the eggs that normally wouldnt have grown but were not making eggs. So if someone starts with ten eggs at the beginning of month, even though they release one egg, theres ten. There we are making those other nine grow in IVF. Were not making eggs from nowhere. Now what happens is when you start. Giving medication to force those eggs to. Grow, the follicles that contain the eggs is what grows. And those follicles get bigger and bigger and bigger. And eventually theres a point where theyre. Ready to be removed, and at that. Point they take a shot, called a. Trigger shot, to make them release those eggs, those follicles. A needle is then placed to pull. The fluid from them, and inside those we find eggs. Those eggs can then be mature or. Immature, and if they're mature, they can be fertilized with sperm, and that can. Be done either with ICSI or with standard insemination, which means either with a needle or just naturally let them fertilize. Then those eggs become embryos, which are single cell embryos. Then those grow out the blastocyst, which. Are essentially the embryo that's going to. Implant into the uterus. Now that we've talked about the progression. Let'S talk about each step. Now, you're going through the IVF process, and you are at the point of measuring the follicles. So you're coming into your doctor's office. Several times a week, and they're looking. At your ovaries and seeing how big. The follicles are getting. As they're getting bigger, they'll say, okay. We see 15 eggs. Now, at some point they're going to be big enough where the doctor is. Being ready to retrieve those eggs and you're going to take that trigger shot. So that is the last point that those eggs have to grow. So from that point, whatever number you. Have is the number of potential eggs. You have, but it is not the. Number of eggs that you can use. So let's use a couple numbers here. Let's just start with ten to make it simple. A lot of people usually do get. Above ten eggs, but it's an easy number to start with for the math. So we start with ten follicles and. Then we go to retrieve the eggs. Usually most doctors get 100% of the eggs. Now it's possible that there could be. Very difficult retrievals and you can end. Up with less eggs. But for this podcast, we're going to assume 100%, because in general, most people do get about 100% of the eggs that they're expecting. There is that rare moment you dont. And usually there is a reason behind. That, whether its the trigger shot was. Bad, whether there was something wrong with the eggs, they were immature, theres even something wrong physically, with that patient. That causes it more difficult to get the eggs. Were going to assume 100%. Now we get all ten eggs. The part we dont know is how many are going to be mature. In my clinic, I do tell people. What I expect to be mature and. Im very conservative with that number. So, for example, I might say to. Them, youre going to get ten eggs, but I only think seven are going to be mature. Your doctor may not give that information ahead of time. So if they dont, youre going to have to assume that not every egg. Is going to be mature. So if we start with those ten. Eggs, there might only be eight that are mature. Now, why this is an important step is because when you have immature eggs, you can't fertilize them right away. Now, if you're doing standard insemination, you can put the sperm with them and. You can hope overnight that they fertilize. But if you're talking about ICSI, you. Really can't fertilize them. Now, a lot of clanks may try, but in the general sense, if they. Never mature, they won't end up becoming an embryo. And so from that ten, assuming that. We get all ten and they're all mature, we expect 70% to 80% of them to fertilize, which means we're only going to get 77 to eight eggs that become embryos. Now, what can affect that? Well, a couple things. So the sperm quality, people who have. Bad sperm may even have poor quality DNA in their sperm and that can affect fertilization. So that 70% could drop down to 50% and now there's only five embryos. Or there could be egg issues. Something wrong with eggs. So women who are more mature, sometimes. Their eggs can die during the fertilization process, sometimes they don't fertilize as well. And so again, that could drop down to 50%. And now you're with five embryos. But let's assume this is the best case scenario. This is a Disney story. So we got eight embryos from those ten eggs. Well, what's interesting is those eight embryos. Are the embryos now that will go on and become blastocyst, and blastocysts have 100 plus cells, whereas the embryo only had one cell. That was just the combination of the. Sperm and egg that make the one cell embryo. And then they grow over these five. Days until they become a blastocyst. And just like you would think, it splits from one to two cells to four cells to eight cells to 16 cells. Then around about the third to fourth. Day, then becomes a morula, where there. Is now 30 something cells that start. To make a kind of dense ball, and then that expands, and that becomes. A blast cyst, which is over 100 cells, usually by day five or six. Now, during this journey from a single. Cell to the blastocyst stage, sometimes they'll stall, for example, sometimes they wont make. It past day three or even past. A single cell stage. Now, we expect about 50% of the embryos being at the single cell stage. To make it to the blastocyst stage. Any good clinic is going to be around that 50%. Now, that doesnt mean youre going to get 50%. If youre someone who is 44, it may be much less if youre someone. Who has really bad sperm. We tend to see sometimes that theyll. Stall around the cellular stage. But again, lets assume were on this Disney story and that of the eight embryos for them make it to the blastocyst stage. So already weve gone from ten eggs. Being retrieved all the way down to four embryos, and well stick with this dizzy story. And this is going to be a princess. So we know shes under 35, because. I dont believe Disney has any princesses above 35, but please correct me if Im wrong. So if they're under 35, we know. That 60% of the eggs are going to be normal. And so we're going to be looking at somewhere around three to two embryos from the blastocyst that would be genetically normal, which means there's one or two. Of them that may be abnormal. And so from those ten eggs, you. Now are left with two or three euploid embryos. Now, what's interesting is for that princess under 35, we know that those three. Embryos, if they put them back sequentially. One at a time, we'd be looking. At around a, 90% chance of a live birth. With the first embryo, it'd be close to around 50. With the second embryo, we'd be close to around 75. And with the third embryo, we would be around 90%. And so for someone under age 35, ten eggs is usually enough to come away with at least one live birth. And what's interesting about that is that's. Also the same number we talk about to have around an 80% chance of live birth when freezing eggs. Ten eggs equals one live birth in women under age 35. So let's use another example. Let's use 20 follicles are there. And of those 20 follicles, we get 20 eggs. Perfect. Of those 20 eggs, maybe 100% immature. So we fertilize them and lets say. With ICSI, 70% now were down to 14 embryos. And from those 14 embryos then well. Be down to seven embryos. Because of the blastocyst, 50% make it there. And from those seven we know about four of them will be genetically normal because the princess is under age 35 and three of them will be genetically abnormal. Now at this point, I wanna make sure that you understand statistics do not present themselves in small sample sizes. What I mean by this is when. I say four should be genetically normal, that doesn't mean all seven can't be completely abnormal. And that's because statistics don't really follow the pattern in small sample sizes. So flip a quarter three times and. You get three heads, still a normal corner. Flip it two more times. Now you have five heads, still a normal quarter. Now you flip that quarter 100 times. And you tell me you get 100 heads. I know either you're lying or you have a, ah, fake quarter. And that's because in larger sample sizes we start to see statistics. And so even if you, let's say, have had four kids, five kids, six kids, and they're all the same gender, we tend to start to think, oh my goodness, this person only makes boys or girls. But in reality you just flip the quarter five or six times. You need to flip that quarter 100 times, meaning have 100 babies before you could truly say that person only makes boys or girls. So how does it pertain to this? Well, I want you to understand that there is always going to be outliers if someone has a very bad sperm sample, if someone has very poor egg quality, all of these statistics can change, but in general, you should think that you're getting close to about 100% of your eggs retrieved. So starting with the follicles, if you. Wanted to be a little bit liberal with that number and say, well, just. In case my fertility doctor doesn't get. All the eggs, assume 90% to 95% will be retrieved. When it comes to fertilization, think somewhere. Between 70% to 90%. And then when it comes to blastulation, think somewhere between 40 and 60%. So I'm taking all clinics in and putting them in there, not our clinic. Using those stats, then you should be able to look at your situation and say, well, how many eggs did I have retrieved? And have a better idea of how many blastocyst youll get. And so it comes to be about 25%. Again, it could be higher up to. 33%, but in general, 25% to 33% is what you expect from the number. Of eggs you have to the number of blastocysts you get. And thats normal. Most people get between around eight to. Twelve eggs and come away with one. To four embryos, which would be normal. Now there are outliers. Like I just said, I had a patient one time, she got something like. 27 eggs, I believe it was. And of those 27 eggs, she got 26 embryos. And I remember she was actually very upset and saying like, well, what happened that last embryo? And im like you just basically pulled. Off a miracle and youre worried about why one egg didnt make it. So sometimes people have very weird expectations. So by you having right expectations, you're going to come away, at least not disappointed. But I've seen people get three eggs. Three blasts from it. All three come back normal. And I've seen other people who have 26 eggs and then end up having. Very few blasts, sometimes even one. This is why I always bring up the point. The most important part is the fertilization. It doesnt matter if you start with a million eggs. If only ten fertilize, you only have ten embryos to work with, and you. Cant get more blastocyst than the beginning embryo number, whether its 100% or 50%. You still have to start with an embryo. So that is going to be the biggest step where you should be not. Worried, but really where youre holding your. Breath because your doctor is not going to have problems getting eggs. That's very uncommon. And fertilization in general can be bad. But in general, it's about, like I. Said, that 70, 80%. But if you have immature eggs, if. You had eggs that are dying at the time of fertilization and you only. End up with a few embryos, that's. Where now it gets a little more scary because now you're dependent on the lab of hoping in every single of those embryos to make it to blastocyst. And if you're older, there's less likelihood that you're going to get good blastulation rates. As I started in the beginning, this. Is not to be a pessimistic view. This is to help people be more prepared and what to expect. If you're expecting the worst, you're going to feel great. Then if you're expecting the best, you could get disappointed, just like I did at that Denny's in Flagstaff. I always tell my kids I have low expectations, and the reason why is because I don't get upset much, because if I keep my expectations low, I won't be disappointed. Now, that doesn't mean you shouldn't keep. Your expectations for having a baby low. That's actually fairly good. Most people who are under 35 who go through IVF will come away with a live birth. If you're age 40 and above, it usually takes two ivfs. But again, very good chances are coming away with a live birth. But one of the most stressful portions of this whole process is that attrition rate. There's just something that feels so wrong that you can start with so many. Aches and then with so few embryos. But the thing I always remind people is this one important thing. The goal was to try to get pregnant. And if that means you have to. Go through 30 eggs or whatever that. Number is to get to that one. Perfect embryo, that's why you did it. You did it to get to that. Perfect embryo to give you the highest chance of success. It's going to be basically your Michael Jordan of embryos. Hopefully, if you're going through IVF, this episode was helpful, and maybe it might help reduce some stress when you went through it. If you have a family member who's going through IVF, or maybe even a friend, let them know about this podcast and let them be prepared for that attrition rate, because that journey from egg to embryo is not as smooth as it looks like it's going to be. As always, if you like this podcast, please tell everyone about it. And if you're on your podcast, review us on your favorite medium. But as always, as always, say, keep coming back. And I look forward to seeing you again next week on Taco Bell fertility Tuesday.