IVF & Treatment Basics
Blastocysts are Day 5 embryos with the highest implantation potential in IVF. Learn how blastocyst grading, Day 3 vs Day 5 transfer, and PGT help improve IVF outcomes at Modi Pluro.
The embryos in the IVF process may not be alike, and one of the key landmarks is the development of blastocysts from the embryos. A blastocyst is a relatively advanced embryo, which normally forms on Day 5 following fertilisation. This is unlike the Day 2 or Day 3 embryos which were used in the early days of IVF.
What is the significance of blastocyst formation in this context? The reason is that the embryos with strong developmental capacity are the ones which develop to blastocyst stage. Embryo culture to Day 5 naturally selects those embryos which would have failed to establish a pregnancy. In simple terms, this implies that blastocyst formation increases the implantation potential of the embryos.
At Modi Pluro in Nagpur, Dr. Modi and the embryology team monitor embryo development carefully. Whether a Day 3 or Day 5 transfer is recommended depends on individual factors, including how many embryos are developing, their quality on Day 3, and the patient's medical history. More embryos don't always mean Day 5 is better; the decision is personalised.
Blastocyst culture also makes it easier to perform preimplantation genetic testing (PGT) if required, for example, in patients with recurrent miscarriage or a family history of genetic conditions. The embryo can be biopsied and tested before transfer, improving the chances of a healthy pregnancy.
If you've had a previous IVF cycle with Day 3 transfers and are wondering whether blastocyst culture could improve your outcome, that's a conversation worth having with Dr. Modi at your next consultation.
Q: Is blastocyst transfer always better than Day 3 transfer?
A: Not always. Blastocyst transfer has higher per-transfer success rates, but if a patient has very few embryos, culturing to Day 5 risks having no embryos survive to transfer. Your embryologist and Dr. Modi will decide together based on your specific cycle.
Q: Can all embryos reach the blastocyst stage?
A: No. Typically 40–60% of fertilised eggs reach blastocyst, depending on egg and sperm quality. Some cycles produce only 1–2 blastocysts from several fertilised eggs, this is normal and reflects natural selection.
Q: What does the blastocyst grading mean?
A: BLASTOCYSTS are evaluated based on their expansion (1–6 scale) and the quality of two cell groups: the inner cell mass (ICM, which becomes the baby) and the trophectoderm (TE, which becomes the placenta)। Grades like 4AA or 3AB show ICM/TE quality and expansion। Your embryo grades will be clearly explained by Dr. Modi's team.
Not always. Blastocyst transfer has higher per-transfer success rates, but if a patient has very few embryos, culturing to Day 5 risks having no embryos survive to transfer. Your embryologist and Dr. Modi will decide together based on your specific cycle.
No. Typically 40–60% of fertilised eggs reach blastocyst, depending on egg and sperm quality. Some cycles produce only 1–2 blastocysts from several fertilised eggs, this is normal and reflects natural selection.
BLASTOCYSTS are evaluated based on their expansion (1–6 scale) and the quality of two cell groups: the inner cell mass (ICM, which becomes the baby) and the trophectoderm (TE, which becomes the placenta)। Grades like 4AA or 3AB show ICM/TE quality and expansion.
