PGT-A Testing in IVF: Is Genetic Screening Worth It?
Complete guide to PGT-A (preimplantation genetic testing). Costs £2,500-4,000, how it works, benefits, risks, who should consider it, and whether genetic screening improves your IVF success.
What does PGT-A test for?
PGT-A tests embryos for the correct number of chromosomes (46 total). Detects aneuploidy (wrong chromosome number), which causes miscarriage, implantation failure, or genetic conditions like Down syndrome.
How much does PGT-A cost?
£2,500-4,000 (UK) or $3,000-6,000 (USA) for biopsy and testing of 8 embryos, plus mandatory frozen transfer (£1,500-2,500 extra). Total: £4,000-6,500 additional cost.
Who should do PGT-A?
Women 38+, recurrent miscarriage patients, multiple failed IVF cycles, many embryos available (8+), or carriers of genetic translocations benefit most.
Key Takeaway: PGT-A tests embryos for correct chromosome numbers (costs £2,500-4,000 extra) and increases pregnancy rates per transfer (60-70% vs 30-40%) by selecting only chromosomally normal embryos. However, it doesn't increase overall live birth rates per egg retrieval because you start with fewer embryos. Best for women 38+, recurrent miscarriage patients, multiple failed IVF, or those with many embryos (8+). Not recommended for women under 35 with few embryos. The test is 95-98% accurate but has limitations with mosaicism. PGT-A reduces miscarriage risk significantly but adds 1-2 months to timeline and has 5-10% embryo damage risk.
Table of Contents
What Is PGT-A?
PGT-A stands for Preimplantation Genetic Testing for Aneuploidy (previously called PGS—Preimplantation Genetic Screening). It's a laboratory procedure that tests IVF embryos for the correct number of chromosomes before transfer.
Chromosomes 101
- •Humans should have 46 chromosomes (23 pairs)
- •22 pairs of autosomes + 1 pair of sex chromosomes (XX or XY)
- •Aneuploidy = Wrong number of chromosomes (too many or too few)
- •Euploidy = Correct number of chromosomes (46 total)
Why Chromosome Number Matters
Aneuploid embryos (wrong chromosome number) usually result in:
- •Failed implantation (60-70% of aneuploid embryos don't implant)
- •Miscarriage (30-40% of aneuploid embryos that implant miscarry in first trimester)
- •Genetic conditions like Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), Patau syndrome (Trisomy 13) if pregnancy continues
PGT-A identifies chromosomally normal (euploid) embryos, allowing you to transfer only those with the best chance of healthy live birth.
Aneuploidy Rates by Age
| Woman's Age | % of Embryos Aneuploid | % of Embryos Euploid (Normal) |
|---|---|---|
| Under 30 | 20-30% | 70-80% |
| 30-34 | 30-40% | 60-70% |
| 35-37 | 40-50% | 50-60% |
| 38-40 | 50-65% | 35-50% |
| 41-42 | 65-80% | 20-35% |
| Over 42 | 80-90% | 10-20% |
Key Insight: Aneuploidy rates increase dramatically with age. This is why IVF success rates decline with age—not just fewer eggs, but higher proportion of chromosomally abnormal eggs. PGT-A becomes increasingly valuable for women over 38.
How PGT-A Works: The Process
Step 1: Standard IVF Cycle
Complete egg retrieval and fertilisation as normal. Embryos are cultured to Day 5 or 6 (blastocyst stage) in the lab. You need to reach blastocyst stage for PGT-A biopsy.
Step 2: Embryo Biopsy (Day 5-6)
An embryologist removes 5-10 cells from the trophectoderm (outer layer of cells that will become the placenta, not the baby). The biopsy is done using a laser to create a small opening and a micropipette to extract cells. The inner cell mass (which becomes the baby) is not touched.
Risk: 5-10% of embryos may not survive the biopsy or subsequent freeze/thaw process.
Step 3: Embryo Freezing (Day 6)
After biopsy, all embryos must be frozen (vitrification). This is mandatory because PGT-A results take 7-14 days to come back, too long for fresh transfer. Freezing also allows embryos to recover from the biopsy stress.
Step 4: Genetic Analysis (7-14 days)
Biopsy samples are sent to a genetics laboratory. DNA is extracted and analyzed using Next-Generation Sequencing (NGS) or array comparative genomic hybridisation (aCGH) to count all 23 chromosome pairs. Results categorize each embryo as:
- • Euploid (normal chromosome count—46 total)
- • Aneuploid (abnormal chromosome count)
- • Mosaic (mix of normal and abnormal cells—5-20% of embryos)
Step 5: Results & Counselling
Your clinic provides a detailed report showing which embryos are euploid, aneuploid, or mosaic. Typically, only euploid embryos are recommended for transfer. Mosaic embryos may be transferred as second choice if no euploid embryos are available (some clinics won't transfer mosaics at all).
Step 6: Frozen Embryo Transfer (1-2 months later)
Once you're ready (next cycle or later), do a frozen embryo transfer (FET) with a selected euploid embryo. Because the embryo is chromosomally normal, you have higher chance of implantation and lower risk of miscarriage.
Important: PGT-A adds 1-2 months to your IVF timeline because it requires a freeze-all cycle and separate FET. You cannot do a fresh transfer with PGT-A.
Cost Breakdown
| Service | UK Cost | USA Cost |
|---|---|---|
| Standard IVF Cycle | £8,000-12,000 | $15,000-25,000 |
| Embryo Biopsy Procedure | £1,000-1,500 | $1,500-2,500 |
| Genetic Testing (up to 8 embryos) | £1,500-2,500 | $2,000-3,500 |
| Additional embryos (per embryo) | £150-300 | $200-400 |
| Embryo Freezing (mandatory) | Included | Included |
| Frozen Embryo Transfer (FET) | £1,500-2,500 | $3,000-5,000 |
| Total: IVF + PGT-A | £12,000-18,500 | $21,500-36,000 |
| Additional Cost vs Standard IVF | £4,000-6,500 | $6,500-11,000 |
Insurance: Most UK health insurance and NHS do not cover PGT-A (considered optional). In the USA, even states with IVF insurance mandates typically exclude PGT-A. Expect to pay out-of-pocket.
Free PGT-A Decision Calculator
Interactive tool to help you decide if PGT-A is worth it based on your age, embryo count, budget, and IVF history. Includes cost-benefit analysis.
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Success Rates & Benefits
Per-Transfer Success Rates
| Age Group | Without PGT-A | With PGT-A (Euploid Embryo) |
|---|---|---|
| Under 35 | 35-45% | 60-70% |
| 35-37 | 28-35% | 60-65% |
| 38-40 | 15-25% | 55-65% |
| Over 40 | 8-15% | 50-60% |
Impressive, right? PGT-A dramatically increases pregnancy rates per embryo transfer because you're only transferring chromosomally normal embryos. However...
Critical Limitation: PGT-A does NOT increase live birth rates per egg retrieval cycle. This is because you start with fewer transferable embryos after excluding aneuploid ones. For women under 35, multiple large studies (including STAR trial, 2019) found no difference in cumulative live birth rates between PGT-A and no testing groups.
Key Benefits of PGT-A
- 1️⃣Reduces Miscarriage Risk
From 20-30% down to 8-12% per pregnancy. Huge emotional benefit for recurrent loss patients.
- 2️⃣Shortens Time to Pregnancy
By avoiding transfers of aneuploid embryos that will fail or miscarry, you reach successful pregnancy faster (fewer failed cycles).
- 3️⃣Helps Embryo Selection
When you have multiple good-looking embryos, PGT-A identifies which are actually chromosomally normal (morphology alone can't tell).
- 4️⃣Explains Failed Cycles
If all embryos come back aneuploid, you know why previous cycles failed—it's egg quality, not uterine or other factors.
- 5️⃣Peace of Mind
Knowing you're transferring a chromosomally healthy embryo reduces anxiety during two-week wait.
Risks & Limitations
1. Embryo Damage from Biopsy
5-10% of embryos may not survive the biopsy procedure or subsequent freeze/thaw. While modern vitrification has excellent survival rates (95-98%), adding biopsy creates additional stress on embryos.
2. False Positives (Mosaicism)
5-20% of embryos are "mosaic"—containing both normal and abnormal cells. The biopsy only tests 5-10 cells from the trophectoderm (placenta), not the inner cell mass (baby). If the biopsy samples abnormal cells but the inner cell mass is normal, a healthy embryo could be incorrectly labeled abnormal and discarded.
Key finding: Studies show 20-40% of mosaic embryos can lead to healthy live births if transferred. Many clinics automatically discard or deprioritize mosaics, potentially wasting viable embryos.
3. No Embryos to Transfer
Risk of all embryos coming back aneuploid increases with age: 20% (under 35), 40-50% (38-40), 60-80% (over 42). If this happens, you've spent £4,000-6,500 extra and have nothing to transfer. You'll need another retrieval cycle.
4. Doesn't Test for Everything
PGT-A only tests chromosome number, not: single gene disorders (need PGT-M for that), structural chromosome rearrangements, mitochondrial issues, uterine factors, or other causes of implantation failure/miscarriage. A euploid embryo can still fail for other reasons.
5. Added Timeline & Cost
Mandatory freeze-all adds 1-2 months to your timeline, plus £4,000-6,500 in additional costs. For women with limited time (age 40+), this delay could impact overall success.
Who Should Consider PGT-A?
✓ Good Candidates
- •Women 38+: 50-80% of embryos aneuploid at this age
- •Recurrent pregnancy loss: 2+ miscarriages (chromosomal abnormalities cause 50-70% of early losses)
- •Multiple failed IVF: 3+ cycles with good-quality embryos that didn't implant
- •Many embryos available: 8+ blastocysts to test (can afford to exclude aneuploid ones)
- •Severe male factor: Higher aneuploidy rates with very low sperm parameters
- •Known chromosomal translocation: You or partner carries genetic rearrangement
- •Want to minimize miscarriage risk: Willing to pay for emotional benefit of lower loss rate
✗ Not Recommended
- •Women under 35, first IVF cycle: No proven benefit, may reduce total embryos available
- •Few embryos (≤3 blastocysts): High risk of zero euploid embryos, biopsy damage, or all-mosaic result
- •Severe diminished ovarian reserve: Every embryo counts—can't afford to exclude any or risk biopsy damage
- •Tight budget: £4,000-6,500 could be better spent on additional IVF cycle
- •Time-sensitive: Can't afford 1-2 month delay for freeze-all cycle
- •Philosophical objection: Uncomfortable discarding aneuploid or mosaic embryos
Is PGT-A Worth It? Decision Framework
Consider PGT-A IF:
You are 38+ years old
→ 50-80% of your embryos are likely aneuploid. PGT-A helps you avoid transferring embryos destined to fail.
You've had 2+ miscarriages or 3+ failed IVF cycles
→ Chromosomal abnormalities may be the cause. PGT-A identifies the issue and reduces future loss.
You have many embryos (8+)
→ Can afford to exclude aneuploid ones and still have multiple euploid embryos to transfer.
Minimizing miscarriage risk is top priority
→ The emotional benefit of 8-12% vs 20-30% miscarriage rate is worth the cost to you.
Skip PGT-A IF:
You are under 35, first IVF cycle, good prognosis
→ 70-80% of your embryos are already euploid. PGT-A won't significantly improve outcomes and costs £4,000-6,500 extra.
You have ≤3 embryos
→ High risk of zero euploid embryos after testing. Every embryo is precious—biopsy damage risk too high.
Budget is very tight
→ £4,000-6,500 could fund half of another IVF cycle, which may give you more chances than testing few embryos.
Your doctor doesn't recommend it
→ Trust your RE's assessment based on your specific situation and history.
Bottom Line: PGT-A is most valuable for women 38+, recurrent loss patients, and those with many embryos to test. For women under 35 with good prognosis, benefits are unclear and may not justify the cost. The decision is highly individual—discuss with your fertility specialist based on your age, embryo numbers, history, and priorities.
Alternatives to PGT-A
1. Morphology-Based Selection
Embryologists grade embryos based on appearance (number of cells, fragmentation, inner cell mass quality). While not as accurate as PGT-A, good morphology correlates with lower aneuploidy rates. "AA" or "AB" graded blastocysts have 60-70% chance of being euploid (vs 50% overall).
Cost: Free (standard IVF)
2. Time-Lapse Imaging (EmbryoScope)
Continuous monitoring of embryo development using time-lapse photography. Algorithms analyze cell division timing, symmetry, and other parameters to predict viability. Some studies suggest time-lapse can identify embryos with higher euploidy rates without invasive biopsy.
Cost: £500-1,000 extra (much cheaper than PGT-A)
3. Non-Invasive PGT-A (niPGT-A)
Emerging technology that tests culture medium (fluid embryo grows in) for DNA shed by embryo, eliminating need for biopsy. Still experimental—not yet widely available or proven as accurate as standard PGT-A. Exciting future option.
Cost: Not yet commercially available
4. Transfer Multiple Untested Embryos
For women under 35, transferring 2 untested embryos (where permitted) may give similar or better cumulative success than testing + transferring 1 euploid, especially if you have few embryos. Risk: higher twin rate (20-30%).
Cost: Free vs £4,000-6,500 for PGT-A