A 2026 study explored how IVF patients emotionally navigated the decision to transfer embryos labelled “abnormal” by PGT-A, with many describing grief, uncertainty, and loss of trust in the testing process.
PGS Testing (PGT-A)
A 2026 meta-analysis examined how well PGT-A biopsies represented the rest of the embryo, and found higher mismatch rates in embryos labeled as aneuploid, especially segmental aneuploid embryos.
Aneuploid embryo success rates after transfer are very low, with about 1–2% leading to a live birth, likely due to undetected mosaicism after PGT-A rather than true whole chromosome aneuploidy.
PGT-A contamination, sometimes reported as “no result,” is poorly studied, but a 2026 study found it’s rare and that undetected contamination can distort PGT results, highlighting the importance of contamination detection in testing.
A 2026 study used a machine learning model to predict whether a miscarriage was euploid or aneuploid using routine medical data, without PGT-A, and showed moderate ability to distinguish between the two while identifying several associated factors.
A 2026 study found that mosaic embryo outcomes vary by type and level, with high-level and trisomy mosaics showing lower success rates, while segmental mosaics had outcomes similar to euploids.
In a 2025 study, researchers masked mosaic PGT-A results and found that mosaic reporting did not meaningfully improve embryo selection or live birth prediction beyond standard criteria, suggesting that PGT-A’s main clinical value lies in identifying clearly aneuploid embryos.
A 2025 study suggests that most patients with recurrent pregnancy loss who transfer up to 3 euploid embryos go on to have a live birth, though data from later transfers are limited.
Using a new non-toxic imaging method, researchers watched living human embryos divide in real time and discovered that chromosome separation errors linked to mosaicism can arise even at the blastocyst stage, showing that mosaicism is a dynamic process rather than one confined to early development.
A 2025 study introduces the FORTUNE model, developed from over 10,000 PGT-A cycles, that uses age, ovarian reserve, partner age, and BMI to predict how many euploid embryos a patient is likely to produce by grouping patients into five prognosis categories.
A 2024 meta-analysis combined the results of 10 studies to show that embryos that are thawed for PGT-A, or rebiopsied after inconclusive results, have lower chances of pregnancy and live birth, with higher miscarriage rates.
This post traces the evolution of PGT-A testing in IVF, from early FISH and microarray methods to modern NGS and emerging technologies like nanopore sequencing, highlighting how each advancement improved accuracy, speed, and embryo assessment.
A new case report describes the healthy birth of dizygotic twin girls from embryos labeled as aneuploid by PGT-A, highlighting the limitations of embryo testing and the need to reconsider strict discard protocols.
Even when embryos are euploid and pass PGT-A, miscarriage can still happen. A new 2025 study suggests that genetic mutations too small to be seen by standard PGT-A may explain some of these losses.
A 2025 study shows that segmental abnormalities detected by PGT-A in the trophectoderm don’t always match the ICM, suggesting that these embryos may still be viable for transfer.
In a 2025 study, researchers estimated how many frozen eggs are needed, by age, to reliably yield three euploid blastocysts or achieve one, two or three live births, offering practical guidance for egg freezing patients.
A 2025 study re-analyzed embryos that tested as mosaic by NGS-based PGT-A using SNP karyotyping and found that one-third of those “mosaics” were actually uniformly aneuploid.
A 2025 opinion article highlights some of the issues with PGT-A, mainly its uncertain benefit, technical flaws, high costs, and the risk of discarding potentially viable embryos.
A 2024 study explored the male and female factors that are associated with embryo euploid rates, finding that male characteristics had a minor influence.
Researchers in 2024 report on live births after segmental aneuploid transfers, finding that they have similar rates as high level mosaic segmental aneuploids.
A 2024 study performed a more sensitive type of PGT-A by analyzing single cells, finding that nearly all blastocysts and fetal tissue contain some level of mosaicism.
Aneuploid embryos, with an abnormal number of chromosomes, are a major cause of miscarriages, often linked to maternal age and errors in meiosis. In this post, we’ll explore what chromosomes and aneuploidy are, how meiosis errors cause aneuploidy, and the factors contributing to these errors, including age, genetics and mitochondrial dysfunction.
A 2024 study compared successful and unsuccessful euploid transfers, finding that female age had no impact, while BMI, embryo quality and the type of FET used did.
In a 2024 study, researchers developed a model to help predict the number of mature eggs needed to obtain at least one euploid, based on age.
The ASRM has released their 2024 committee opinion on the use of PGT-A, covering the use of PGT-A for patients with a good prognosis, advanced age, donor eggs, recurrent pregnancy loss and more.