PGT-A Genetic Testing: Your Guide to Smarter Embryo Selection

How genetic screening can help you choose the embryo with the best chance of becoming your baby

📖 14 min read ✅ Medically reviewed 📅 Updated January 2025

✨ The Empowering Truth About PGT-A

  • PGT-A helps identify which embryos have the best chance of success
  • Euploid (chromosomally normal) embryos have 60-70% live birth rates per transfer
  • Modern testing is 97-99% accurate for whole chromosome abnormalities
  • It's especially valuable for women 35+ and those who've experienced loss
  • Colombia offers PGT-A at 50-70% lower cost than the US

If you're exploring IVF, you've probably heard about PGT-A (Preimplantation Genetic Testing for Aneuploidy). It sounds technical, but here's the beautiful simplicity: PGT-A helps you identify which of your embryos have the right number of chromosomes—giving you the best possible shot at a successful pregnancy.

Think of it as giving your embryos a health check before transfer, so you can make the most informed choice about which one to welcome into your uterus. Let's explore everything you need to know to decide if PGT-A is right for your journey.

What Exactly Is PGT-A?

PGT-A screens embryos for aneuploidy—having too many or too few chromosomes. Humans have 46 chromosomes (23 pairs), and embryos need exactly this number to develop normally. Extra or missing chromosomes are the leading cause of:

Here's the encouraging news: by identifying embryos with the correct chromosome count (called euploid embryos), PGT-A dramatically improves your chances of a successful pregnancy per transfer.

60-70%

Live birth rate per transfer of a PGT-A tested euploid embryo

How PGT-A Works: A Simple Breakdown

Step 1: Embryo Development (Days 1-5)

After your eggs are retrieved and fertilized, embryos grow in the lab for 5-6 days until they reach the blastocyst stage—a hollow ball of about 100+ cells. This is the perfect time for testing because there are enough cells to safely biopsy.

Step 2: Trophectoderm Biopsy (Day 5-6)

A skilled embryologist carefully removes 5-10 cells from the trophectoderm—the outer layer that will become the placenta. The inner cell mass (which becomes your baby) is left completely untouched. This procedure has been performed millions of times worldwide with excellent safety records.

Step 3: Genetic Analysis (1-2 Weeks)

The biopsied cells are analyzed using Next-Generation Sequencing (NGS), the gold standard technology that examines all 24 chromosome types (22 pairs plus X and Y). Modern NGS has 97-99% accuracy for detecting whole chromosome abnormalities.

Step 4: Results & Transfer

You'll receive a report showing which embryos are euploid (normal), aneuploid (abnormal), or mosaic (a mix—more on this later). You and your doctor can then choose the best embryo for transfer with confidence.

💡 Good to Know

During the biopsy and testing period, your embryos are safely frozen (vitrified). This actually works in your favor—frozen embryo transfers often have equal or better success rates because your body has time to recover from stimulation.

The Numbers: PGT-A Success Rates

Let's look at what the research actually shows—and it's genuinely encouraging:

Outcome Measure Euploid Embryo Untested Embryo
Implantation Rate 65-70% 35-45%
Clinical Pregnancy Rate 65-75% 40-50%
Live Birth Rate (per transfer) 60-70% 30-40%
Miscarriage Rate 7-12% 15-25%

A 2025 study from CCRM found that even for women under 35, choosing embryos based on PGT-A results led to a 76.7% live birth rate compared to 53.4% using morphology (appearance) alone. That's 23 additional babies born per 100 women—a meaningful difference.

🎯 Important Distinction

PGT-A improves success per transfer, not necessarily per retrieval cycle. If you have multiple euploid embryos, your cumulative chances are excellent. The goal is efficiency—fewer transfers to achieve your family.

Who Benefits Most from PGT-A?

PGT-A isn't required for everyone, but certain situations make it especially valuable:

✅ Strong Candidates

  • Age 35+ — Aneuploidy rates increase significantly
  • Recurrent miscarriage — Often caused by chromosomal issues
  • Previous failed transfers — Rule out embryo quality
  • Known chromosomal concerns — Family history
  • Single embryo transfer preference — Choose with confidence

🤔 Consider Your Situation

  • Under 35 with good prognosis — Benefits less clear
  • Very few embryos — May not change decision
  • Cost is a major concern — Calculate cost per baby
  • Philosophical objections — Personal values matter

The Age Factor: Why It Matters So Much

Here's the biological reality that makes PGT-A increasingly valuable with age:

Maternal Age % of Embryos Expected to Be Euploid
Under 35 60-70%
35-37 50-60%
38-40 30-40%
41-42 20-30%
43+ 10-20%

At 38, roughly half your embryos may have chromosomal abnormalities—even if they look perfect under the microscope. By 43, it might be 80-90%. PGT-A helps you find the winners in your cohort.

Understanding Your Results

Euploid (Normal) ✅

These embryos have 46 chromosomes—the correct number. They have the highest chance of implanting, developing normally, and resulting in a healthy baby. These are your priority for transfer.

Aneuploid (Abnormal) ❌

These embryos have missing or extra chromosomes. They typically either won't implant or will result in early miscarriage. In rare cases, some aneuploidies (like trisomy 21) can result in live birth with chromosomal conditions. Most clinics don't recommend transferring aneuploid embryos.

Mosaic (Mixed) 🔶

About 10-15% of tested embryos show mosaicism—a mix of normal and abnormal cells. Here's the hopeful news: mosaic embryos can and do result in healthy babies! Success rates are lower than euploid (roughly 27-40% live birth rate), but they're a viable option when no euploid embryos are available.

💡 Mosaic Embryos: The Hopeful Reality

Research shows that embryos have remarkable self-correcting abilities. Many mosaic embryos can "fix" themselves as they develop, pushing abnormal cells to the placenta while the baby develops normally. Genetic counseling helps you understand your specific mosaic embryo's potential.

The Different Types of PGT

PGT-A is just one type of preimplantation genetic testing. Here's the full picture:

Test Type What It Screens For Who Needs It
PGT-A Chromosome number (aneuploidy) Anyone wanting to optimize transfer success
PGT-M Specific genetic diseases (cystic fibrosis, sickle cell, etc.) Carriers of known genetic conditions
PGT-SR Structural chromosome rearrangements Those with translocations or inversions

If you're a carrier of a genetic disease, you may want PGT-M in addition to or instead of PGT-A. Your genetic counselor can help determine the right testing strategy.

Cost of PGT-A: US vs. Colombia

PGT-A adds cost to your IVF cycle, but the value calculation often makes sense—especially when you factor in avoided failed transfers and miscarriages.

Embryo Biopsy (per embryo) US: $250-400 Colombia: $100-200
Genetic Analysis (per embryo) US: $300-500 Colombia: $150-300
Total per Cycle (5-8 embryos) US: $3,000-6,000 Colombia: $1,500-3,000
Genetic Counseling US: $200-500 Colombia: Often included

The Real Cost-Benefit Math

Consider this scenario: A 38-year-old woman without PGT-A might need 2-3 transfers (and potentially experience a miscarriage) to achieve a live birth. With PGT-A identifying a euploid embryo, she might succeed on her first transfer.

The math often favors testing, especially for women over 35 or those with limited emotional bandwidth for repeated attempts.

What the Latest Research Says (2024-2025)

The ASRM's Updated Position

The American Society for Reproductive Medicine's 2024 committee opinion acknowledges that while PGT-A shows clear benefits in improving per-transfer success rates, the evidence for improving cumulative live birth rates (across all embryos from one retrieval) is less clear-cut. Translation: PGT-A helps you get pregnant faster with fewer transfers, but if you have many embryos and unlimited patience, you might eventually succeed either way.

The NEJM Study

A large randomized trial found that among women under 37 with three or more good-quality blastocysts, cumulative live birth rates were similar with or without PGT-A. However, PGT-A still offered faster time to pregnancy and fewer transfers—meaningful benefits for many patients.

The CCRM 2025 Findings

The latest research from CCRM showed that even young, first-time IVF patients had significantly higher live birth rates when embryos were selected by PGT-A rather than appearance alone—suggesting benefits across all age groups.

🎯 The Bottom Line

PGT-A is a powerful tool for optimizing your journey. It's especially valuable if you want to minimize transfers, reduce miscarriage risk, or are 35+. It's less essential if you're young with many embryos and comfortable with a "try and see" approach.

PGT-A: Common Questions Answered

Does the biopsy harm the embryo?
Modern trophectoderm biopsy is remarkably safe. The cells removed come from the outer layer that becomes the placenta, not the baby. Studies show no increased risk of birth defects or developmental issues. Millions of babies have been born after PGT-A worldwide.
Can PGT-A detect all genetic problems?
PGT-A detects chromosome number abnormalities (aneuploidy) but not single-gene disorders, small deletions, or mutations. It also can't detect conditions that develop after conception. Prenatal testing is still recommended even after PGT-A.
What if all my embryos are abnormal?
This can happen, especially for older patients—but it's valuable information. You might consider another retrieval cycle, donor eggs, or transferring a low-risk mosaic embryo with genetic counseling. Knowing beats wondering.
Does PGT-A guarantee a healthy baby?
No test is 100%. PGT-A significantly improves your odds but can't guarantee outcomes. There's a small false-positive rate (healthy embryos incorrectly labeled abnormal) and false-negative rate. It's one powerful tool in your toolkit.
Can I do gender selection with PGT-A?
Yes—PGT-A identifies sex chromosomes (XX or XY). Family balancing is permitted in Colombia and the US. Some patients use this for medical reasons (sex-linked genetic conditions), others for personal preference.

PGT-A in Colombia: World-Class Testing at Accessible Prices

Colombian fertility clinics offer PGT-A using the same NGS technology as top US centers—often performed in partnership with internationally accredited genetic laboratories. The difference? Cost savings of 50-70% without compromising quality.

Leading Colombian clinics like InSer in Medellín and Conceptum in Bogotá have performed thousands of PGT-A cycles with outcomes matching international benchmarks. Many employ embryologists trained in Europe and the US, and results are typically available within 7-14 days.

Ready to Learn More About PGT-A in Colombia?

Our partner clinics offer comprehensive genetic testing with genetic counseling included. Get clarity on whether PGT-A is right for your journey.

Request a Free Consultation

Making Your Decision

PGT-A is a personal choice, and there's no universally "right" answer. Consider these questions:

Whatever you decide, know that both paths—testing and not testing—lead many patients to their babies. PGT-A is about optimizing your journey, not the only way to succeed.