A 2025 study introduces the term “oocyte and early embryo competence defects” to describe younger IVF patients who repeatedly have no transferable embryos due to low quality eggs, finding that about 13–23% had genetic changes.
Embryo arrest
A 2025 study of women with repeated IVF failure and unexplained infertility found that about 13% had mutations affecting egg or embryo development, mostly in the TUBB8 and PATL2 genes, suggesting that many “unexplained” cases may have underlying genetic causes.
Researchers in a 2024 study showed that by artificially removing the embryo’s zona (shell) right after fertilization reduced fragmentation, improved blastocyst development, and led to live births in patients with repeated IVF failure, though the findings are still preliminary and need confirmation in larger trials.
A 2025 study suggests that acetaminophen (Tylenol), at levels reached after a standard dose, can disrupt embryo development in experimental models, raising questions about its potential impact on IVF outcomes, although better research in humans is needed before changing clinical practice.
In a 2025 study, researchers tested a noninvasive MRI-like tool that reads an embryo’s metabolic health, accurately predicting which would stop developing and potentially helping select the healthiest for transfer.
A 2024 meta-analysis combined the results of 12 studies comparing the use of artificial oocyte activation (AOA) on IVF outcomes. They found that there were increases in fertilization and live birth rates, but only in patients with a history of fertilization problems.
A 2024 case report details a patient who had success transferring a 4 cell embryo on day 4 — an embryo that some clinics wouldn’t have considered for transfer.
Researchers in a 2021 review examined how sperm and eggs can sometimes be genetically incompatible, based on a group of proteins called human leukocyte antigens (HLA), which may lead to implantation failure or embryo arrest when they’re mismatched.
Embryo arrest is when an embryo stops developing, usually before reaching the blastocyst stage. This post explains possible causes, including embryonic genome activation, maternal effect genes, the subcortical maternal complex, aneuploidy, mitochondrial dysfunction, oxidative stress, lab conditions, and sperm DNA fragmentation.