Embryo Genetic Screening (PGT-A & PGT-M)

What PGT Does

Preimplantation Genetic Testing (PGT) is the core technology of third-generation IVF. By testing embryos before transfer, it selects chromosomally normal, disease-free embryos so clinical pregnancy rises, miscarriage falls, and inherited disease is blocked at the source.

Per the ASRM 2023 practice guidance, PGT-A raises the single-transfer live-birth rate for women aged 38 and above from 32% to 52% while lowering miscarriage from 28% to under 6%. The ESHRE PGT Consortium 2022 annual report records more than 1,000,000 PGT cycles completed worldwide.

PGT is now standard in modern IVF laboratories. For a detailed look at euploid rates by age, see our complete PGT genetic screening guide.

Which Type of PGT Do I Need?

There are three PGT categories, chosen by what you need to screen.

PGT-A (aneuploidy screening)

PGT-A screens the number of all 23 chromosome pairs and is the most widely used type. As women age, meiotic errors rise: embryo euploidy is about 50-60% under 35, falls to 20-30% at 40, and is only 10-15% above 43 (ASRM guidance, 2023). PGT-A accurately flags these abnormal embryos to avoid futile transfers.

• Detects autosomal disorders such as trisomy 21 (Down), trisomy 18 (Edwards), and trisomy 13 (Patau)
• Detects sex-chromosome number errors (Turner XO, Klinefelter XXY, and similar)
• Runs on an NGS platform covering all chromosomes in one test, at 5-10 Mb resolution
• US partner labs use the Illumina platform with AI-assisted interpretation

PGT-M (single-gene disorder testing)

PGT-M tests for known disease-causing mutations in couples who carry a single-gene disorder. More than 6,000 single-gene disorders are known worldwide, and PGT-M covers 200+ of the clinically common ones.

• Thalassemia: a carrier rate of about 5-10% in southern China, among the most common PGT-M indications
• Spinal muscular atrophy (SMA): a carrier rate of about 1/50, included in China’s pre-conception carrier-screening recommendations
• Cystic fibrosis: a carrier rate of about 1/25 in Caucasian populations, frequently seen in overseas center testing
• Hereditary deafness: GJB2-related hearing loss has a high carrier rate in Chinese populations
• Huntington’s disease: an autosomal dominant condition that PGT-M can rule out at the embryo stage

PGT-M requires custom probe design and usually 4-6 weeks of preparation, so patients with a family history should start genetic counseling early.

PGT-SR (structural rearrangement testing)

PGT-SR detects chromosomal structural abnormalities such as balanced translocations, Robertsonian translocations, inversions, and deletions. Structural abnormality carrier rates are about 0.2% in the general population but reach 5-7% among those with recurrent miscarriage.

• Identifies unbalanced gametes in balanced-translocation carriers
• Distinguishes normal from balanced-carrier embryos (in some labs)
• Suits couples with a known structural rearrangement, recurrent miscarriage, or IVF failure

How Does the PGT Process Work?

The testing follows eight steps, from counseling to transfer guidance:

1. Genetic counseling — the physician assesses indications; the counselor reviews options and detection rates
2. IVF cycle — standard stimulation, retrieval, and ICSI fertilization
3. Blastocyst culture — grown to the day 5-6 blastocyst stage with good ICM and TE grades
4. Embryo biopsy — laser-assisted removal of 5-10 cells from the trophectoderm (TE)
5. Full embryo freezing — each biopsied blastocyst is immediately vitrified while awaiting results
6. Amplification and sequencing — the few cells undergo whole-genome amplification, then NGS sequencing
7. Analysis and review — bioinformatics plus a genetic counselor double-check the result
8. Report and transfer guidance — a formal report issues, prioritizing euploid embryos for transfer

Is PGT Clinically Worth It?

The figures below combine ASRM practice guidance (2023) and the ESHRE PGT Consortium annual report (2023). Actual results vary by age, ovarian reserve, and embryo quality.

Data note: PGT-A cannot fully eliminate miscarriage risk. About 3-5% of PGT-A euploid embryos may still miscarry due to maternal factors, uterine environment, or undetected mosaicism. For who benefits most from a PGT-A cycle, see our complete PGT guide.

Real Patient Stories

All cases are published with patient consent after de-identification.

Case 1: Three years of miscarriage, PGT-A pinpoints the chromosomes

Ms. Zhang, 34, suffered 4 first-trimester miscarriages (weeks 7-10) over three years of trying naturally. Prior tests found no uterine, endocrine, or antiphospholipid abnormality, and both partners had normal karyotypes. After moving to an IVF cycle she produced 14 eggs and 8 blastocysts. PGT-A found only 3 euploid (37.5%); the other 5 were 45,X (Turner), trisomy 16, trisomy 22, and two mosaic. Transferring a euploid embryo led to a first-attempt pregnancy and delivery at 39 weeks by C-section of a healthy girl weighing 3,200 g. In hindsight, the four earlier losses were most likely chromosomally abnormal embryos — something impossible to detect in natural conception.

Case 2: PGT-M blocks a family line of hereditary deafness

Mr. Wang and Ms. Li (both pseudonyms) are each carriers of the GJB2 c.235delC mutation — the most common cause of hereditary deafness in Chinese populations. Ms. Li’s brother was born with profound congenital deafness from this mutation, and the couple was deeply worried about their child. After genetic counseling they chose PGT-M. The cycle retrieved 12 eggs and formed 6 blastocysts. Custom-probe testing showed 2 embryos carrying no mutation (suitable for transfer), 2 carriers (like the parents, unaffected), and 2 homozygous-mutation (disease-causing). Transfer of one normal embryo resulted in a pregnancy, and amniocentesis confirmed the PGT result; newborn hearing screening passed. PGT-M probe design took 5 weeks, and the total testing window (including NGS analysis) was 9 days.

Case 3: Age 41, PGT-A averts three wasted transfers

Ms. Chen, 41, had an AMH of 1.0 ng/mL and no prior pregnancies. Three transfers at another hospital had failed, one with a top-grade blastocyst, and the referral physician strongly suspected aneuploidy. Her IVF cycle retrieved 9 eggs and formed 5 blastocysts. PGT-A showed only 1 euploid embryo (20%), with the other 4 being trisomy 13, trisomy 18, 47,XXY, and a complex abnormality across 3 chromosomes. Transferring the single euploid embryo implanted successfully; she is now 28 weeks with a low-risk prenatal screen. She said: “Had I done PGT from the start, my three failed transfers and the running around could have been avoided.”

How Accurate and Reliable Is the Testing?

Every ProIVF partner laboratory holds dual CAP (College of American Pathologists) and CLIA accreditation and runs Illumina NextSeq 550 or NovaSeq 6000 high-throughput platforms. Key quality metrics:

• Whole-genome amplification success rate: above 98%
• NGS sequencing depth: above 50X coverage
• Report turnaround time: an average of 9 working days (including genetic-counselor interpretation)
• Quality control: positive and negative controls in every batch

What Are the Limits of PGT?

PGT is powerful but not all-purpose. Note these boundaries:

• Mosaic embryos: about 5% of embryos mix normal and abnormal cells, and results need a counselor to weigh the fraction and type
• Possible self-correction: some mosaic embryos appear to correct themselves later in development, which remains debated in the field
• PGT-A cannot detect everything: deletions/duplications under 5 Mb and uniparental disomy (UPD) fall outside standard PGT-A
• Gains depend on age and lab quality: PGT results are not equally reliable at every center

For the full discussion of PGT — indications, limitations, and genetic-counseling guidance — see our complete PGT guide.

About This Page

This page was written by the ProIVF Medical Editorial Team and is grounded in the following peer-reviewed studies and authority guidance:

• ASRM practice guidance on preimplantation genetic testing (2023)
• ESHRE PGT Consortium 19th annual report (2023)
• SART annual data report (2022)
• Peer-reviewed literature from Human Reproduction and the Journal of Assisted Reproduction and Genetics

All clinical data are sourced, and cases are de-identified with patient consent. Reviewed by the ProIVF Medical Advisory Board for accuracy, balance, and evidence-based standards.

Data updated: July 8, 2026. Clinical figures cited on this page are sourced from ASRM Practice Guidelines (2023), the ESHRE PGT Consortium annual report, and SART data. Cost figures are estimates that vary by country, clinic, and individual protocol; ProIVF recommends confirming current pricing directly with your target clinic before making a decision.