A 2025 meta-analysis combined 151 studies on interventions for advanced maternal age (>35) patients. It found no clear advantage to any specific stimulation protocol or FSH type, no benefit from routine ICSI, and decreased live birth with assisted hatching, while more research is needed on blastocyst versus cleavage-stage transfer and on PGT-A with modern methods.
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 2023 study found that probiotic supplementation had no impact on positive hCG pregnancy rates, but may improve miscarriage rates.
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.