A 4AA is one of the grades families search most after an embryology report. In Gardner notation the first digit is expansion, the first letter is inner cell mass (ICM), and the second letter is trophectoderm (TE). A 4 means an expanded blastocyst still inside a thinning shell; both A letters mean the lab described dense, well-formed cell groups on that day. That reading is about appearance, not a promise of implantation or live birth.
Planning aid for family building — not medical advice, not a personal success rate, and not a clinical opinion for your case.
4AA = expansion 4 · ICM A · trophectoderm A. Decode each field below, then use the interactive tool with this grade preloaded.
Many 4AA grades are assigned on day 5, but day-6 and day-7 reports can use the same string when the embryo reaches that morphology later. Later development does not automatically make a grade “worse,” and earlier development does not guarantee a better clinical outcome. Ask your clinic whether the grade was scored at freeze, at transfer, or both, and whether PGT was performed on the same embryo.
Gardner-style blastocyst grades describe how an embryo looks under the microscope on the day of freeze or transfer: expansion of the fluid cavity (1–6), quality of the inner cell mass that may become the fetus (A–C), and quality of the trophectoderm that becomes placenta (A–C). Morphology is one planning signal among many. It is not a personal success rate. Clinics differ in how they assign letters, and day-5, day-6, and day-7 embryos can carry the same letter string with different context. Society for Assisted Reproductive Technology (SART) clinic reports and peer-reviewed embryology literature discuss morphology alongside age, embryo cohort, and PGT when used — never grade alone as a prediction for your case.
Paste a Gardner-style grade from your lab report (for example 4AA or D5 4AB). This translates fields into readable language — it does not score success odds.
Report grade entered as 4AA. In Gardner-style notation, 4AA describes expansion 4, ICM A, and trophectoderm A. This is a translation aid, not a ranking of embryo quality or a prediction of live birth.
Gardner-style blastocyst notation decoder with plain-English field translation. Educational only; clinic reports and counseling govern care.
Planning aid for family building — not medical, legal, or tax advice, and not a clinical opinion for your case.
It is often described as a strong morphological appearance, but labs do not use a universal “best” label, and higher-looking morphology does not translate into a personal success percentage on a public page. Transfer order depends on your whole cohort, clinical history, and any genetic testing policy at your clinic.
No. Morphology describes how the embryo looked that day. Implantation and ongoing pregnancy depend on many factors your reproductive endocrinologist and embryology team interpret together.
Many clinics freeze and transfer day-6 blastocysts when morphology and other criteria are acceptable. Whether a specific embryo is a candidate is a clinical decision for your team.
