PGT-A Genetic Testing: Is It Right for Your IVF Cycle?

If you're undergoing IVF, you've likely heard the term PGT-A — Preimplantation Genetic Testing for Aneuploidy. It's one of the most discussed and debated topics in fertility treatment today. This guide breaks down exactly what PGT-A is, how it works, what it costs, and most importantly, whether it might be right for your IVF cycle.

What Is PGT-A?

PGT-A (Preimplantation Genetic Testing for Aneuploidy) — formerly known as PGS (Preimplantation Genetic Screening) — is a laboratory test that checks embryos for chromosomal abnormalities before they are transferred to the uterus during IVF.

Every human cell should contain 46 chromosomes arranged in 23 pairs. An aneuploid embryo has an abnormal number of chromosomes — either too many or too few. The most well-known example is Down syndrome (trisomy 21), where there are three copies of chromosome 21 instead of two.

PGT-A screens all 23 pairs of chromosomes to identify which embryos have the correct number, helping fertility specialists select the embryo with the best chance of resulting in a healthy pregnancy.

How PGT-A Works: The Biopsy Process

PGT-A is performed during the blastocyst stage of embryo development, typically on Day 5 or Day 6 after fertilization. Here's the step-by-step process:

Step 1: Embryo Culture to Blastocyst

After egg retrieval and fertilization via ICSI (intracytoplasmic sperm injection), embryos are cultured in the laboratory for 5-6 days until they reach the blastocyst stage — a ball of approximately 100-200 cells with two distinct cell types: the inner cell mass (which becomes the fetus) and the trophectoderm (which becomes the placenta).

Step 2: Trophectoderm Biopsy

Using a specialized laser and micropipette under a high-powered microscope, an embryologist carefully removes 3-10 cells from the trophectoderm (the outer layer that will form the placenta). This is critical — cells are taken from the part that becomes the placenta, not the part that becomes the baby, minimizing any potential harm to the developing embryo.

Step 3: Genetic Analysis

The biopsied cells are sent to a genetics laboratory where they undergo Next-Generation Sequencing (NGS), the current gold standard for PGT-A. NGS can detect even small chromosomal gains or losses (segmental aneuploidies) and mosaic patterns. Results typically return within 7-14 days.

Step 4: Embryo Freezing

After biopsy, embryos are vitrified (flash-frozen) and stored while awaiting results. A frozen embryo transfer (FET) is then scheduled in a subsequent cycle when the uterine lining is optimally prepared.

Who Should Consider PGT-A?

PGT-A is not mandatory for all IVF patients, but certain groups may benefit significantly:

• Women aged 35 and older: Aneuploidy rates increase dramatically with maternal age. At 35, approximately 50% of embryos may be aneuploid; by 42, this rises to over 80%.
• Recurrent miscarriage: Women who have experienced two or more miscarriages, as chromosomal abnormalities are the leading cause of early pregnancy loss.
• Previous IVF failure: Those who have had multiple failed IVF cycles despite good-quality embryos, particularly if implantation failure is suspected.
• Recurrent implantation failure: When euploid embryo transfer can help distinguish between embryo-related and uterine-related causes of failure.
• Family balancing: Some patients use PGT-A to identify the sex of embryos (where legally permitted), though this remains a secondary application.
• Severe male factor infertility: In some cases, sperm abnormalities can increase aneuploidy risk.

Euploid vs Aneuploid vs Mosaic: Understanding Your Results

PGT-A results classify embryos into three categories:

Euploid (Chromosomally Normal)

A euploid embryo has the correct number of chromosomes — 46 in total, with 23 pairs. These embryos have the highest chance of implantation and live birth. When a euploid embryo is transferred, implantation rates range from 60-70%, and miscarriage rates drop below 10%.

Aneuploid (Chromosomally Abnormal)

An aneuploid embryo has an abnormal number of chromosomes. Common aneuploidies include trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), trisomy 13 (Patau syndrome), and monosomy X (Turner syndrome). Most clinics recommend against transferring aneuploid embryos due to high miscarriage rates and potential health complications if a live birth occurs.

Mosaic

A mosaic embryo contains a mix of normal and abnormal cells within the same embryo. Mosaicism occurs in approximately 10-20% of blastocysts. Results are typically reported as:

• Low-level mosaic (20-40% abnormal cells): Higher chance of self-correction and healthy live birth.
• High-level mosaic (40-80% abnormal cells): Lower success rates but still possible.

Many mosaic embryos can self-correct during development, as normal cells may outcompete abnormal ones. Transfer decisions should be made after thorough genetic counseling.

PGT-A Success Rates: What the Data Shows

Multiple large-scale studies have examined how PGT-A affects IVF outcomes. Here's what the evidence tells us:

• Implantation rate per transfer: Transferring a euploid embryo results in a 60-70% implantation rate, compared to 40-50% for untested embryos in women under 35.
• Miscarriage reduction: The miscarriage rate after euploid embryo transfer is approximately 8-10%, versus 15-25% without PGT-A.
• Time to pregnancy: By avoiding transfers of aneuploid embryos (which would either fail to implant or miscarry), PGT-A can reduce the number of transfer cycles needed to achieve pregnancy.
• Live birth per egg retrieval: PGT-A does not increase the total number of babies born from a single egg retrieval — it helps identify which embryos to transfer first.

For women over 35, the benefit is more pronounced because a higher proportion of embryos are aneuploid. PGT-A helps avoid futile transfers and the emotional toll of failed cycles or miscarriages.

PGT-A Cost Breakdown

PGT-A adds a significant cost to the IVF cycle. Here's what you can expect to pay in 2026:

Cost Component	Estimated Range (USD)
Embryo biopsy fee (per cycle)	$1,500 - $2,500
Genetic testing fee (per embryo batch, up to 8 embryos)	$1,500 - $3,000
Additional embryos (per embryo beyond batch limit)	$200 - $400 each
Embryo freezing & storage (first year)	$800 - $1,200
Total estimated cost	$3,000 - $5,000+

Risks and Limitations

While PGT-A is a powerful tool, it's important to understand its limitations:

• No test is 100% accurate: PGT-A has approximately 97-98% accuracy. False positives (labeling a normal embryo as abnormal) and false negatives (missing an abnormality) occur in about 2-3% of cases.
• Embryo damage risk: Though very rare (<1%), the biopsy process can potentially damage an embryo.
• Mosaic uncertainty: Mosaic results create difficult decisions for patients, as outcomes are less predictable.
• No guarantee of pregnancy: Even a euploid embryo may not implant due to uterine factors, immunological issues, or other unknown causes.
• Cost barrier: The additional $3,000-5,000 may be prohibitive for some patients.
• Embryo discard concerns: Some patients have ethical concerns about discarding aneuploid embryos.
• Segmental aneuploidies: Small chromosomal deletions or duplications may be below the detection threshold of standard NGS.

PGT-A vs PGT-M vs PGT-SR: What's the Difference?

There are three types of preimplantation genetic testing, each serving a different purpose:

Feature	PGT-A	PGT-M	PGT-SR
Full Name	PGT for Aneuploidy	PGT for Monogenic Disorders	PGT for Structural Rearrangements
What It Tests	Chromosome number (all 23 pairs)	Single-gene mutations (CF, sickle cell, etc.)	Chromosomal rearrangements (translocations, inversions)
Who Needs It	Advanced maternal age, recurrent loss, prior IVF failure	Known carriers of genetic disorders	Carriers of balanced translocations or inversions
Test Development	Standardized — same for all patients	Custom probe created per family (8-12 weeks prep)	Custom probe may be needed
Cost	$3,000 - $5,000	$5,000 - $12,000+	$4,000 - $8,000

These tests can be combined. For example, a couple carrying a genetic disorder may undergo both PGT-M (to screen for the specific mutation) and PGT-A (to ensure chromosomal normality) simultaneously.

Frequently Asked Questions