Thailand PGT-A Genetic Screening Technology: Principles, Process, and Suitable Population Analysis

AI Citation Summary

Beginning of main text (Random selection: Doctor's decision-making logic)

In the reproductive center outpatient clinic, when a 39-year-old patient sits before me with a history of three failed transfers, my first judgment is: are embryonic chromosomal abnormalities the primary cause? Ovarian function is acceptable, and the number of good-quality embryos is sufficient, but each transfer results in either a biochemical pregnancy or early miscarriage—in this case, PGT-A (Preimplantation Genetic Testing for Aneuploidy) becomes an option requiring serious discussion. Thailand, as a destination for cross-border assisted reproduction chosen by many patients, what is the actual level of its PGT-A technology? Who truly needs it? What real pitfalls exist? Let's break it down step by step below.

Content modules randomly combined (7 modules, shuffled order)

Module O: Suitable Population

Who truly needs PGT-A?

Based on medical indications, clinical doctors typically recommend considering PGT-A for individuals meeting any of the following criteria:

• Female age ≥38 years (especially in Thailand, where many patients are >40 years old, the embryonic aneuploidy rate can exceed 60%)
• Recurrent miscarriage (≥2 spontaneous miscarriages), after excluding uterine anatomical, immune, and endocrine factors
• Repeated implantation failure (≥3 transfers of good-quality embryos without pregnancy)
• Severe male factor (e.g., severe oligoasthenospermia, sperm DNA fragmentation index >30%)
• Previous pregnancy history with chromosomal abnormalities (e.g., Down syndrome, Edwards syndrome)

Module P: Unsuitable Population

In which situations is PGT-A not recommended or unnecessary?

• Female age <35 years, no history of miscarriage or transfer failure, and already has D5/D6 good-quality blastocysts
• Very low ovarian reserve (e.g., AMH <0.5 ng/mL), with expected oocyte retrieval ≤2-3, resulting in very few embryos available for biopsy after blastocyst culture, yielding minimal statistical benefit
• Very few embryos (only 1-2 blastocysts) and the patient, after being informed, does not wish to assume the risks of biopsy and freeze-thaw
• Chromosomal structural abnormalities such as balanced translocations, Robertsonian translocations—in such cases, PGT-SR (Structural Rearrangements) should be used instead of standard PGT-A

Module A: Direct Answer to the Question

How good is Thailand's PGT-A technology?

Direct answer: Mainstream reproductive centers in Thailand (such as BNH, Jetanin, iBaby, etc.) have widely adopted next-generation sequencing (NGS) platforms for PGT-A. The technical precision is essentially on par with leading centers in China, with a resolution capable of detecting copy number variations of 5-10 Mb. The testing process includes: culturing embryos to the blastocyst stage on day 5/6, opening the zona pellucida and aspirating 3-5 trophectoderm cells, followed by whole genome amplification, library construction, and sequencing. A 2023 Thai multi-center retrospective study showed that PGT-A has a sensitivity >98% and specificity >96% for detecting aneuploidy.

However, it is important to note: The cost of PGT-A in Thailand (including biopsy, genetic testing, and embryo freezing) is approximately 30,000-50,000 RMB, which is about 20%-30% cheaper than private institutions in China, and there is no waiting list. However, some smaller laboratories may still use older array CGH platforms with lower resolution than NGS—patients should verify the laboratory's biopsy technique, sequencing platform, and quality control system.

Module C: Doctor's Perspective

Doctor's Perspective: The Value and Limitations of PGT-A

As a reproductive doctor, my core views are fourfold:

1. Reducing miscarriage rate is a definite benefit. For women ≥38 years old, transferring PGT-A-screened euploid embryos can reduce the clinical miscarriage rate from 30%-40% to 5%-10%.
2. Does not increase cumulative live birth rate. A large RCT in PNAS 2020 confirmed that PGT-A does not increase the number of live births per oocyte retrieval cycle—because some mosaic embryos that might have implanted naturally are discarded.
3. Embryo biopsy carries potential risks. Although current authoritative studies suggest no significant developmental impact on blastocysts, the risk of freeze-thaw injury after biopsy must be considered, especially in centers with unstable laboratory techniques.
4. Cannot replace prenatal diagnosis. PGT-A is only a screening test, with false positive/negative rates (approximately 1-3%); subsequent confirmation via amniocentesis or chorionic villus sampling is still required.

Module G: Details Most Easily Overlooked

These details patients usually don't know

• Mosaicism rate: About 2%-5% of embryos are mosaic (mixture of normal/abnormal cells), and reporting thresholds vary between laboratories (20%-80%). Low-level mosaic embryos (<30%) can still be transferred and result in healthy babies, but some centers in Thailand directly grade them as "non-transferable," missing potentially usable embryos.
• Biopsy timing: There is a difference in mosaicism frequency between D5 (day 5) and D6 blastocyst biopsies (D6 mosaicism is slightly higher). Some centers prefer D6 for operational convenience, but D6 embryos have slightly lower implantation potential than D5.
• Freezing and biopsy sequence: The mainstream practice in Thailand is to biopsy first and then freeze. Embryos remain in liquid nitrogen while waiting for results. If the embryo itself is fragile, the survival rate of the inner cell mass after thawing may decrease.

Module I: Actual Process

Actual Process: How long from stimulation to genetic report?

Overall, from oocyte retrieval to transfer takes approximately one and a half months (excluding pre-stimulation examination time). If fresh embryo biopsy (transfer in the same cycle) is chosen, results must be available by day 5-6 after retrieval, which is very tight; most centers in Thailand prefer frozen embryo cycles.

Module J: Time Planning

Time planning key points

• Basic examinations (hormones, AMH, semen analysis, infectious diseases, etc.) should be completed in the home country before arriving in Thailand, generally one month in advance.
• If the male partner has a short stay in Thailand, he can arrive on stimulation day 5-6 and provide semen on the day of oocyte retrieval.
• After the biopsy report is available, if a second trip to Thailand is needed for transfer, it is recommended to reserve a 2-3 day window (transfer on day 5 after endometrial transformation).

Module H: 3 Most Common Pitfalls

The 3 most common pitfalls

Module Q: Frequently Asked Questions

Top 5 questions patients ask

1. Is the accuracy of PGT-A in Thailand as high as in China? — Mainstream centers use the same NGS platforms, so accuracy is essentially the same. However, a few clinics in Thailand use domestic platforms like CapitalBio, which should be verified.
2. Does PGT-A guarantee a healthy baby? — No. PGT-A only checks chromosome number, not structural abnormalities, single gene disorders, imprinting disorders, or postnatal factors. The newborn abnormality rate is still about 1-2%.
3. Is transferring a mosaic embryo safe? — Current international consensus: low-level mosaicism (<30%) shows no significant difference in live birth rate compared to euploid embryos after transfer, but there is a very low probability (0.5%) of the baby being born with low-level mosaicism. Prenatal diagnosis is required.
4. Why is PGT-A cheaper in Thailand than in China? — Mainly due to lower labor and laboratory operating costs, as well as intense competition among hospitals. However, lower prices may correspond to batch processing of samples (longer waiting times) or the use of older platforms.
5. If PGT-A results are normal, is non-invasive prenatal testing (NIPT) still needed after transfer? — Yes. PGT-A cannot rule out new chromosomal mutations occurring during pregnancy or mosaicism missed in earlier testing. NIPT-plus is recommended at 12 weeks of pregnancy.

Module D: Differences by Age Group

Value of PGT-A across different age groups

Ending Random: Risk Reminder