Decoding hCG: Can One Number Predict Your Pregnancy?

The two-week wait after fertility treatment can feel endless, but what if a single blood test could give you insight into your pregnancy’s future? In this episode of Taco Bout Fertility Tuesday, we break down the science behind hCG levels at 16 days post-ovulation and how they predict pregnancy outcomes. We’ll discuss the role of hCG beyond just a pregnancy test, how it rescues the corpus luteum to sustain early pregnancy, and why progesterone supplementation changes how miscarriages present in fertility treatments. Plus, we analyze a key study from Fertility & Sterility (2000) to understand how different hCG levels correlate with pregnancy success or loss. Whether you're in the midst of an IVF cycle or just love diving into the science of fertility, this episode is packed with valuable insights. Tune in to learn what your hCG levels really mean and how to interpret them with your doctor!

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

0:00

Today we talk about how a single HCG test can predict the outcome of an IVA pregnancy. Giving hope or setting expectations right from the start. I'DOCTOR Mark Amols, and this is Taco about Fertility Tuesday. When undergoing fertility treatments, the two week wait to find out if you're pregnant can feel like an eternity. But what if a single blood test could give you a strong indication of whether your pregnancy will continue or not? Well, research has shown that ACG levels at just 16 days after ovulation can be a powerful predictor of success. And today we're going to dive into the science behind these numbers. What do they really mean and how can they guide your expectations? Whether you're in the midst of an IVF cycle or just curious about the science of early pregnancy, this episode is for you. Now, before we get into the nitty gritty of what HCG levels mean, what let's talk about what is the purpose of hcg? I don't think you're going to be surprised that God didnt make HCG just to use it as a pregnancy test. It's actually a very critical function in early pregnancy. It'produced from the placental cells, specifically the syncyidiotrophopblastic cells, usually starting around six to eight days post fertilization. And the purpose of this hormone is to mimic deuteenizing hormone. And the purpose of that is to keep the corpus luteum from degrading. See, every month when you ovulate, the sac that releases the egg ends up producing progesterone. And that sac will stick around for approximately two weeks and then it will degrade. And when it degrades, thegestion levels will drop and that will lead to IM menses. However, when you get pregnant, you do not want it to drop, otherwise you would lose the pregnancy. So to stop the corpus luteum from degrading, the placenta cells make 8 CG, which looks like the hormone LH, which the body was producing before to make the progesterone, but now it's being produced by the baby. And that keeps the corpus luteum from the gradating, which keeps progestero levels up and keeps the pregnancy moving forward. Essentially, ACG rescues the corpus lutum, allowing it to continue producing progesterone until the placenta can take over around 8 to 10 weeks of pregnancy. Prior to that point, it is the corpus luteum that'producing all the progesterone needed for the pregnancy, which is being run by the HCG from the synidiorophoblast of the placenta. This is very important when you start talking about bleeding and pregnancy. When you get pregnant naturally, if something goes wrong with the baby, then that means HCG will not be produced by the placenta, which will lead to a progesterone drop, which will then lead to the pregnancy being lost and bleeding. But when you do fertility treatment, sometimes you take progesterone and that progesterone will be there regardless if the pregnancy is doing well or not. Meaning the corpus luteum doesn't need to have HCG to keep going. So if something's wrong with a baby and the Hg levels drop, there won't be a drop in the progesterone triggering bleeding. Instead, you could technically have a miscarriage and never know it without a drop of blood because the progesterone you are giving, it's what's protecting the pregnancy and protecting you from bleeding. This is why some miscarriages that occur infertility treatment will occur without any bleeding at all. Overall, the point is, ACG is not just a pregnancy marker. It's actually a signal that rescues the corpus luteum to keep it alive and sustain the pregnancy in the earliest weeks until later when the placenta can be self sufficient and produce all the progesterone needs by itself. This is also the reason why when you ovulate, whether you're doing a modified natural FET or iui, you only need to supplement the progesterone, which can be vaginal versus when you'doing a frozen embryo transfer and you're not ovulating, you need to support the progesterone completely because youe not supplementing, youre providing all of it. The idea for this podcast came from a published article in the Journal of Fertility and Sterility. It was volume 73, issued two in February of 2000 and it was titled Human Chorionic Gnaturropin as a Predictor of Outcome in Assisted Reproductive Technology. Pregnancies essentially can HCG level tell us whether the pregnancy has a better chance at to continue or to not. So lets break down what the study did show. It was a retrospective analysis of 662 ART pregnancies, meaning fertility treatment pregnancies. Retrospective means it wasnt done, prospectively where they had pregnancies and saw what happened. Instead they looked back at data, of prior prenies in the past and that's how they analyzed the data. They measured ACG at just one point, day 16 post ovulation. This would correspond to 10 days after an embryo Transfer and the goal of the study was to determine if a single HCG test could predict pregnancy outcome. Now, this is important to understand. This does not mean that these things say that your pregnancy will go good or go bad. It's just saying if you only have one number, what would it predict? So let's talk about the key findings. Essentially, when they looked at the EG level they broke up into categories 25 to 50, 50 to 100, 100 to 200, 200 to 500, 500 to 1000 and greater than 1000. When you were looking at the 25 to 50 international units per liter, they found that the ongoing pregnancy rate probability was less than 35% and that the miscarriage rate was greater than 65%. When they looked at the 50 to 100 international units per liter, they found that the ongoing princical rate was 35 to 64% and that the miscarriage rate was 36 to 65%. When they looked at the 100 to 200 international units of ACG per liter, they found that 64 to 80% of the pregnancies had ongoing probability and that the miscarri risk was down to 20 to 36%. When they looked at 200 to 500 international units per liter, the ongoing pregnancy probability was 80 to 95%. And now the miscarriion rate was only 5 to 20%. Now when they looked at 500 international units to 1000 in that quarter category, 95 to 100% had ongoing pregnancies and the miscards risk was only 0% to 5%. And when they looked at people with over 1000 for that first ACG level, 100% had ongoing pregnancy rates and the miscary rate was zero. So let's talk about what this means. Does this mean if your ECG is under 50 that you're not going to have a successful pregnancy? Not at all. It's just saying statistically if you take a group of people and you look at their Hg levels and it's below 50, then the ongoing pregnancy rate ends up dropping less than 50%. Specifically under 35%. Now it's important to understand that it has to be 16 days post opvulation. If you do your ACG early, it's going to be lower. If you put back two embryos, it may be higher than expected. There are even some studies that show that when you do PGT that by biopsy the embryo you actually can lower the ACG levels a little bit. It's also important to understand this is A range they're not saying under 50. So what that means is that it could be 30, 40, 45 up to 50, and there could be slight differences between those. But as A group under 50 is under 35, although I don't have the data, I would suspect if you were 48, it probably was very similar to the group that was around 50. So the largest takeaway from this is that if the ECG is below 50 international units per liter, the pry is highly unlikely to continue. But that doesn't mean in your specific situation it's just in general. But if the ECG is above 500, the chances of our ongoing preentancy is very high. Now its'important to understand they didnt look at things like doubling of the hcg, they didn't look at progesterone levels. Fact they didn't even factor in age as much. All of these things can definitely factor. It doesnt matter if your first ACG is 500. If it is 500 but its not doubling, something could be wrong. The same thing. It was noted that women who were over 40 years of age needed higher Hg levels compared to their peers who are younger than them to have the same probability of ongoing pregnancy. Now as you can see, 50 to 500 is a very wide range. Most people don't fall into that. Most people might be 100, maybe they're 300. The reason they chose such wide points is because then they could show that at the extreme sides there is some major difference. The other point to consider is whether you did pgta not just is the ECG level going to be lower, but we also know the miscarriage risk is going to be lower. Like all studies, you have to evaluate whether it had strength and where the weaknesses were. In this study there were some good things. For example, the sample size was good at 662 pregnancies. Additionally, I like the fact that they standardized the timing of the bloodshot at 16 days post ovulation. This ensures consistency. So when we're comparing apples to apples, I also like the idea that it was broad and the fact that it wasn't just IVF but also IUIs. And they also used logistic regression. That was a strong statistical method for binary outcomes, which helped support their claims. Now the limitations of the study is the fact that it was retrospective, meaning it wasn't randomized. So there's the potential for selection bias. They also did analyze ECG doubling rates which is another important factor and I feel could definitely affect the results. They also didn't Control for confounders like the embryo quality or PGT or underlying fertility conditions that may affect it as well. The other thing was during the study they did change the ACG testing method, which may cause some inconsistency. Overall, I, give the study a B. Clinically useful, but not the gold standard when it comes to studies. I would love to see a prospective randomized study and maybe confirm some of the confounders that could be affecting it. But understand why they didn't do that because it wasn't large than enough sample size to be able to add all those other things. So the most important question for you is how can you use this data? I think overall it can just help with your expectations. In the end, always talk to your doctor because they're going to look at things like if the ACG is doubling and also look at your situation. Someone who has s never had a miscarriage or someone who has had multiple miscarriages, we're going to have different expectations. And I'm not going to rely on just a number. At our clinic, we tell people as long as it's 50, we feel pretty good. Now that doesn't mean if I see 200, I don't feel good too. But I also don't feel amazing because it's higher. They use a very high cutoff rate for showing things are great. But in reality that's not a number most people get. It's like saying, well, if you play basketball and youre 6 foot, youre going to do very well, but if you're 10ft tall, well then you're going to definitely do well. Well, that's a very extreme height and so sure it's going to give you a high probabilityability of success, but it's not very reasonable. And that's what I felt with a study. 500 is not a very common number. People say on their first ACG level. If you really want to know how things are going, you look at the doubling rate, you look at the initial hcg and you look at other factors like the quality of the embryo. And also if they did pgta, no matter what, you always want to repeat the acg. At our clinic, we even now check it a third time. So we don't even just look for doubling, but we check a third time. And that's because when we first started we would just do the first two ACGs as long as they doubled. We would set everyone up for an OB scan and about 1% of the time or less, we would start seeing people come in and there'd be no baby in the uterus. So after that we then add it to a third test. And after doing that, we rarely ever see someone come in and not see a pregnancy in the uterus. And that's because we now know with three data points it's very unlikely that it's just going to be a chemical miscarriage. So Does a low H.G. always be miscarriage? Not always. But if there is an increased risk, can a high HCG level predict twins? Yeah, sometimes it can, but it's not definitive. And can this test guarantee in a healthy pregnancy? Well, the answer to that is no. It only predicts the likelihood, not the viability. Think of it as an OD predictor. Overall, use this study to help you predict the success of the pregnancy. Understand that ACCG is more than just a test, it a lifeline of the early pregnancy. And although the single number that you get 16 days post opvulation may be a strong predictor, but the best way to predict is by looking at doubling levels, talking to your doctor so they can take the whole picture and put that together to really give you the right expectations. If you found this episode helpful, share with someone going through ivf, maybe some fertility treatment. If you have questions about the hcg, reach out to your doctor and ask them. Fertility is a very stressful journey and hopefully this episode will help you feel a little bit more comfortable. When you see the HCG level, don't be worried if it'not 500 above. Again, that's not very common. They picked that number because it was able to then say oh look, these all do very well but in reality most people will not be at 500, but most are usually above 100. And what the study showed was that if youre above 100 youre looking at an 80% chance of potentially having a successful pregnancy. As always, if you like this podcast please tell us about it. We really like to hear that. Tell your friends about it and as always, give a five star review on your favorite medium. The most important thing is to keep coming back. I look forward to talking you again next week on Taco Belt Fertility Tuesday.