PGT-A Explained — Should You Genetically Test Your Embryos?
PGT-A — preimplantation genetic testing for aneuploidy — answers the question IVF can’t answer by looking at an embryo under a microscope: does this embryo have the right number of chromosomes? A beautiful-looking blastocyst can carry an extra or missing chromosome that guarantees failure — either no implantation, early miscarriage, or, rarely, a chromosomal condition. PGT-A identifies these before transfer, so you only use embryos with a real chance of becoming a healthy baby.
How It Works
On day 5 or 6 of embryo culture, the embryologist removes 5–10 cells from the trophectoderm (the outer layer that becomes the placenta — the inner cell mass that becomes the baby is untouched). The biopsy is sent to a genetics lab while the embryo is vitrified. Results return in 1–2 weeks: each embryo is reported as euploid (normal chromosome count — suitable for transfer), aneuploid (abnormal — not transferred), or mosaic (a mix of normal and abnormal cells — discussed case by case).
Only euploid embryos are thawed and transferred in a subsequent frozen embryo transfer cycle.
Who Benefits Most
- Women 37+: the proportion of aneuploid embryos rises steeply with age — 40% at 37, 60% at 40, 80%+ at 43. Without testing, most transfers at these ages use aneuploid embryos that can’t succeed. PGT-A converts multiple failed transfers into one informed transfer.
- Recurrent miscarriage: if losses are chromosomally driven, PGT-A selects only normal embryos, reducing loss rates to near the population baseline. Recurrent miscarriage guide.
- Repeated implantation failure: multiple good-looking embryos transferred with no pregnancy — chromosomal issues are the most common hidden cause.
- Single embryo transfer commitment: when you’re transferring one embryo at a time, choosing the chromosomally normal one matters enormously.
- Couples with known translocation: PGT-SR (a variant) identifies embryos that inherited the balanced or normal form rather than the unbalanced one.
Who Might Not Need It
Women under 35 with no history of loss or failure: at this age, 60–70% of embryos are euploid — the per-transfer success rate without testing is already high, and testing adds cost without dramatically changing outcomes. Some clinics still recommend it for peace of mind or to avoid the small chance of transferring an aneuploid; others save the expense for patients where the yield is clearer.
The pragmatic answer: if you’re producing many embryos at a young age and your first transfer succeeds, PGT-A would have been an unnecessary cost. If your first transfer fails, the next conversation includes testing. The trick is that you can’t know which scenario you’re in beforehand — which is why some couples test regardless and others take their chances. Neither is wrong.
Cost
₹30,000–₹60,000 added to the IVF cycle, typically covering the biopsy procedure and genetic analysis for up to 4–6 embryos. Additional embryos may cost extra per unit. The total is meaningful — but measured against the cost of 2–3 failed untested transfers (₹40,000–70,000 each for FET), testing often saves money by avoiding transfers that couldn’t have worked.
Limitations — the Honest Footnotes
PGT-A doesn’t guarantee pregnancy. A euploid embryo has a 60–70% chance of implanting — excellent, but not 100%. Factors beyond chromosomes (endometrial receptivity, immune environment, embryo quality) still matter.
Mosaic embryos create grey zones. Some mosaics can produce healthy pregnancies; others can’t. The decision to transfer a mosaic when no euploid embryos exist is nuanced and best made with genetic counselling.
Biopsy is not risk-free. Skilled labs report embryo survival rates above 99%, but the procedure requires experienced hands — another reason lab quality matters.
False results occur rarely. The biopsy samples the placenta-precursor, not the baby-precursor — occasionally these differ (confined placental mosaicism). The rate is low but non-zero.
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