Does embryo grading matter after PGT-A?

Yes. Grading and chromosome testing assess different things, and both are used together. PGT-A tells you about chromosome number. Grading assesses how the embryo looks — the expansion of the blastocyst, the appearance of the inner cell mass which becomes the baby, and the trophectoderm which becomes the placenta. A euploid embryo with poor morphology and a euploid embryo with excellent morphology are not equivalent. Most clinics transfer the best-graded euploid embryo first. One point from the laboratory literature worth knowing: of the components graded, trophectoderm appearance has been found to be the statistically significant independent predictor of live birth after adjusting for other factors. That is somewhat counter-intuitive, since the trophectoderm becomes the placenta rather than the baby. A caution on grading generally: it is a subjective assessment, and laboratories vary. The Vienna Consensus on laboratory performance describes grading systems as not robust and better suited to internal quality assessment than to comparison between clinics. So a grade from one laboratory is not directly comparable to another's. Grading also does not override a genetic result. A beautifully graded aneuploid embryo is still aneuploid. If you have several euploid embryos, ask your clinic how they rank them and why. If you have one, grading matters less — it is the embryo you have.