In DOR patients, a 2025 study found that follicles measuring 15–17 mm at the time of egg retrieval were associated with the best outcomes, suggesting that optimal trigger timing in this group might occur earlier than standard thresholds used for normal responders.
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.
In a 2025 study, researchers found that poor mitochondrial activity limits the ability of immature eggs to reach maturity, leading to reduced maturation in eggs from older women.
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.
A 2025 case report describes a live birth from a frozen immature egg matured through rescue IVM, suggesting that immature eggs in freezing cycles may have reproductive potential and should not be routinely discarded.
Researchers performed rescue IVM on immature eggs collected from poor prognosis patients, and found that a large number became mature and fertilized, allowing about 1 in 12 patients to have a live birth that they wouldn’t have had otherwise.
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.
Researchers in a 2023 study found that older women that are triggered earlier produce immature eggs that may be more competent than mature eggs after rescue IVM.
Researchers in a 2023 study used rescue IVM and found that many immature eggs became mature and had comparable fertilization and euploid rates to sibling mature eggs, although there was a decrease in blastocyst formation rates.
Researchers in a 2023 study used a procedure called “rescue in vitro maturation” to culture immature eggs collected after retrieval overnight, and found that a high proportion became mature and had comparable fertilization to sibling mature eggs, with many going on to form euploids.
Researchers in a 2022 study compared outcomes from mature M2 eggs and M1-M2 eggs that underwent “rescue in vitro maturation” and found that M2 eggs had improved fertilization, blastocyst conversion and euploidy rates, with no difference in pregnancy or live birth rates.
What’s the ideal follicle size for IVF? Researchers in a 2022 study compared follicle size at the time of trigger and related it to rates for egg maturity, fertilization, good quality embryos and euploidy. They also examined the association between follicle size and age and BMI.
Researchers in a 2020 study compared IVF outcomes by follicle sizes, and found that larger follicles generally produced mature eggs that were more likely to develop into blastocysts.
