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.
This post summarizes the 2025 ESHRE/ALPHA Istanbul consensus on egg and embryo assessment, offering patients a clear overview of how embryologists evaluate and rank eggs, zygotes, and embryos based on updated international guidelines.
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.
A 2024 study found that beta-hCG levels were related to day 3 and day 5 embryo quality and development, with blastocyst expansion having the strongest impact on both initial beta values and their doubling.
A 2024 study compared IVF outcomes and pregnancy rates for patients of different ages (<32 to >40) who had their first single embryo transfer.
Researchers in a 2023 study found that live birth rates depend on a blastocyst’s grade, and not their day 3 grade, while miscarriage rates were affected due to day 3 cell number.
Researchers in a 2022 study performed a meta-analysis to combine the results of studies examining the transfer of a good and poor quality embryo together (vs one good quality embryo alone), and found no differences in pregnancy or live birth rates, but increases in the rate of multiples.
This post takes a closer look at what “poor-quality” embryos really mean in IVF. At the cleavage stage, they often have fewer cells or high fragmentation, while at the blastocyst stage, a grade C means the inner cell mass and trophectoderm contain fewer, loosely packed cells. These embryos tend to have lower success rates than good-quality ones, but studies show they can have similar perinatal outcomes.
Not sure what your embryo grade means—or if it affects your chances of success? This guide walks you through everything from day 3 and day 5 grading systems to what each number and letter combo (like 3BB or 5AA) actually means. You’ll also find success rate research, embryo photos, and insights from a former embryologist to help make sense of your report.