Imagine you are going through IVF. You have several embryos created, and a new test promises to pick the one with the lowest genetic risk for future health problems like heart disease or diabetes. It sounds like a way to give your child the best start in life. But a new study shows this promise may be much smaller than we thought.
This research looks at a tool called Polygenic Embryo Screening (PES). It checks an embryo’s DNA to estimate its risk for common diseases. The goal is to transfer the embryo with the lowest risk. But this study found that in real-world IVF, the benefits are often tiny.
IVF, or in-vitro fertilization, helps millions of couples have babies. It involves creating embryos in a lab and transferring them to the uterus. PES is a new add-on service. It claims to lower the chance your child will get heart disease, diabetes, or other conditions later in life.
This sounds great. But earlier models predicted huge benefits—up to a 50% lower risk. Those models assumed something that rarely happens in real life: that every embryo transfer leads to a live birth. In reality, IVF often requires multiple tries. Sometimes, it doesn’t work at all.
This study tested those predictions against real IVF data. It asks a simple question: Does this expensive screening actually help the average couple?
The Promise vs. The Reality
The old way of thinking was simple. If you have 10 embryos, you can pick the one with the best genetic score. That should cut disease rates in the next generation. But here’s the twist: IVF doesn’t work like that.
In real life, you might only have one or two embryos. Even with several, the first transfer might not stick. You might need to try again with another embryo. This reality changes everything.
The study found that for typical infertility patients, the benefit of PES is very small. We are talking about a risk reduction of just 1% to 3%. That is a far cry from the 50% once promised.
How It Works: A Simple Analogy
Think of PES like picking the best apple from a basket. Each apple has a hidden score for how long it will stay fresh. The old model assumed you could pick the top apple and it would last forever.
But IVF is more like a game of chance. You pick an apple, but it might not "grow" into a tree (a successful birth). If it doesn’t, you go back to the basket. The problem is, the basket might be small, and the apples might not be as good as you hoped.
This study shows that the "success rate" of each transfer is the key factor. If transfers often fail, the benefit of picking the "best" apple first is much lower.
Researchers used data from over 6,900 IVF cycles in Italy. They looked at real patients and egg donors. They simulated what would happen if they applied PES to these cycles. They tracked which embryos were transferred and which led to live births.
They compared the genetic risk of the baby born with PES to the risk of a baby born without it. This gave them a realistic estimate of the benefit.
The results were clear. For most infertility patients, the benefit is minimal. In cycles where all embryos were transferred and at least one child was born, the risk reduction was only about 1-3%. When looking at all completed cycles (even those with no birth), the benefit dropped below 0.5%.
The benefit increases with more embryos and younger maternal age. But for the average patient, these numbers are low.
Here’s where it gets interesting. The tool works much better for egg donors. Donors are young and healthy, and they often produce many embryos. In donor cycles, the risk reduction reached about 20% in a single cycle. This is still lower than the old 50% prediction, but it is much more significant.
But There’s a Catch
This doesn’t mean this screening is available or useful for everyone.
The study found that pooling all embryos from one patient across multiple cycles increased the benefit to 5-10%. But this requires having multiple IVF cycles, which is costly and emotionally draining. For a single cycle, the benefit for a typical patient is often too small to justify the cost and effort.
The researchers conclude that for most infertility patients, PES offers little practical benefit. The ethical and social issues of offering this test to the general population need more attention. The focus should be on who benefits most, like young egg donors, rather than marketing it to everyone.
If you are considering IVF and PES, be realistic. This test is not a magic bullet. For many couples, the chance of having a healthy baby is not significantly improved by this screening.
Talk to your doctor about your specific situation. If you are young and have many embryos, the benefit might be higher. But for most, the cost and emotional weight may not be worth the small gain.
This study used data from one country (Italy) and simulated risk scores. Real-world genetic risks and IVF success rates can vary. The study also focused on specific diseases like heart attack and diabetes. The benefits for other conditions might differ.
More research is needed to see how PES performs in other populations. Future studies should look at the long-term health of children born using this screening. Ethical questions about genetic selection also need more discussion. For now, the promise of PES is much smaller than initially thought, especially for the average IVF patient.
