What Is PGT-A?
Preimplantation Genetic Testing for Aneuploidy (PGT-A) — previously called PGS — screens embryos created through IVF for chromosomal abnormalities before transfer.
The test checks whether embryos have the correct number of chromosomes (46 in humans). Embryos with extra or missing chromosomes (aneuploid) are the leading cause of:
- IVF failure
- Early miscarriage (>50% of early losses are chromosomally abnormal)
- Conditions like Down syndrome (trisomy 21)
How PGT-A Works in Korea
Step-by-Step Process
| Step | What Happens |
|---|---|
| 1. IVF stimulation & retrieval | Eggs retrieved and fertilized as usual |
| 2. Embryo culture to blastocyst | Embryos grown to Day 5–6 (blastocyst stage) |
| 3. Trophectoderm biopsy | 5–10 cells removed from outer layer (not the embryo itself) |
| 4. Vitrification | Embryo is frozen while awaiting results |
| 5. NGS analysis | Next-generation sequencing analyzes all 24 chromosomes |
| 6. Results (7–14 days) | Embryos classified: euploid (normal), aneuploid, or mosaic |
| 7. FET | Normal embryo thawed and transferred in next cycle |
Korean labs use Next-Generation Sequencing (NGS) — the most accurate method, detecting copy number variations across all chromosomes.
Who Should Consider PGT-A?
Strong Candidates
| Patient Profile | Reason |
|---|---|
| Age 37+ | Aneuploidy rate rises sharply with age |
| Recurrent implantation failure (3+ failed transfers) | Chromosomal issues may be the cause |
| Recurrent pregnancy loss (2+ miscarriages) | Majority caused by chromosomal abnormalities |
| Prior chromosomally abnormal pregnancy | Higher risk of recurrence |
| Severe male factor infertility | Higher sperm DNA fragmentation → abnormal embryos |
| Reduced ovarian reserve | Fewer embryos → maximize each transfer |
May Not Benefit
- Women under 35 with no prior failure — natural selection via failed implantation has similar outcomes in some studies
- Patients with only 1–2 embryos (biopsy risk vs. benefit)
Success Rate Impact
| Age Group | Transfer success without PGT-A | Transfer success with PGT-A (euploid) |
|---|---|---|
| Under 35 | ~50% | ~65–70% |
| 35–37 | ~40% | ~60–65% |
| 38–40 | ~30% | ~55–65% |
| Over 40 | ~15–25% | ~50–60% |
Key insight: PGT-A doesn't create more euploid embryos — it identifies which ones are normal, so you transfer the right embryo first. This reduces miscarriage rates by 50–70% in high-risk groups.
Mosaic Embryos
Some embryos test as mosaic — a mix of normal and abnormal cells. These are not the same as fully aneuploid embryos:
- Mosaic embryos can sometimes self-correct during development
- Leading Korean clinics offer mosaic embryo transfer protocols with careful monitoring
- Live birth rates from mosaic transfers: 30–50% (lower than euploid, but higher than no transfer)
Cost of PGT-A in Korea
| Item | Cost (KRW) | Approx. USD |
|---|---|---|
| PGT-A testing (per embryo) | 300,000–500,000 | $225–$375 |
| Biopsy procedure fee | 200,000–400,000 | $150–$300 |
| PGT-A per embryo (total) | 500,000–900,000 | $375–$675 |
| Typical cost for 3–5 embryos | 1,500,000–4,500,000 | $1,125–$3,375 |
PGT-A adds cost to an IVF cycle but reduces total cost per live birth by avoiding failed transfers and miscarriages.
Comparison: PGT-A in the USA typically costs $3,000–$6,000 per cycle (lab fees alone). Korea offers the same NGS technology at 40–60% lower cost.
PGT-A vs PGT-M vs PGT-SR
| Test | Screens For | Who It's For |
|---|---|---|
| PGT-A | Chromosomal number (aneuploidy) | General IVF patients, age-related risk |
| PGT-M | Single gene disorders (e.g., BRCA, CF, SMA) | Carriers of known genetic conditions |
| PGT-SR | Chromosomal structural rearrangements | Couples with translocations or inversions |
Korean clinics offer all three types. PGT-M requires additional preparation time (4–8 weeks for probe design).
For International Patients
Timeline Considerations
- PGT-A adds 7–14 days between biopsy and transfer
- This means the transfer cannot happen in the same fresh cycle → always results in frozen embryo transfer (FET)
- Plan for two trips: one for stimulation/retrieval + biopsy, one for FET (3–5 days)
- Or: retrieve in Korea, return home, then come back for FET 4–6 weeks later
Questions to Ask Your Clinic
- Which NGS platform do you use for PGT-A analysis?
- What is your euploid rate by age group for your patient population?
- Do you offer mosaic embryo transfer, and under what conditions?
- How many embryos typically need to be biopsied to get one euploid?
- What happens to aneuploid embryos — can they be stored or must they be discarded?
FAQ
Q. Is PGT-A mandatory for IVF in Korea?
No. It's optional and decided based on your clinical profile. Your doctor will recommend it if your history suggests you'd benefit.
Q. Can I do PGT-A if I only have 1–2 embryos?
Clinicians often advise against biopsying very few embryos — the 3–5% biopsy damage risk and the chance an aneuploid embryo might still implant (especially in younger patients) may not justify testing. Discuss with your specialist.
Q. Will my home country's fertility clinic accept Korean PGT-A results?
Most will. Korean labs use internationally standardized NGS methods. Bring the full cytogenetics report (usually in English) when consulting your home clinic.
📧 For hospital consultation and referral inquiries, contact: info@bronis.co.kr
Medical Disclaimer: This guide is for informational purposes only. PGT-A decisions should be made in consultation with a licensed reproductive endocrinologist based on your specific clinical history.