The PGT-A Controversy: Is This Common IVF Test Harming Patient Success?

Preimplantation Genetic Testing for Aneuploidy (PGT-A) is one of the most common add-ons in modern IVF treatment. It's offered by fertility clinics worldwide with the promise of increasing live birth rates, reducing miscarriage risk, and helping patients avoid the heartbreak of failed embryo transfers.

Yet a growing chorus of patients, researchers, and even some fertility specialists are asking a difficult question: Is PGT-A always helpful, or could it sometimes be harmful?

The controversy centers on a troubling possibility: that PGT-A, despite its sophisticated technology, may lead couples to discard potentially viable embryos—embryos that could have resulted in healthy babies. Some patients have filed lawsuits claiming they were misled about the test's accuracy.[1] Others have shared stories of conceiving healthy children from embryos that PGT-A had labeled "abnormal."

This article will dive deep into the PGT-A controversy, exploring both the purported benefits and the significant criticisms. Our goal is not to tell you whether to use PGT-A, but to ensure you have the complete picture so you can have a truly informed conversation with your fertility team.

What we'll cover:

The promise and purported benefits of PGT-A
Three key criticisms driving the controversy
The complex issue of mosaic embryos
How to approach PGT-A decision-making with your clinic

The Promise of PGT-A: Why Is It Recommended?

Before diving into the criticisms, it's essential to understand why PGT-A became so popular in the first place. Let's fairly present the "pro" argument.

The Goal of PGT-A

PGT-A screens embryos for aneuploidy—having an abnormal number of chromosomes. A normal human embryo should have 46 chromosomes (23 pairs). Having too many or too few chromosomes is called aneuploidy, and it's a leading cause of implantation failure, miscarriage, and pregnancy loss.

The goal of PGT-A is simple: identify and transfer only chromosomally normal (euploid) embryos, thereby improving IVF outcomes.

The Purported Benefits

Proponents of PGT-A point to several potential advantages:

Increased Implantation Rate Per Transfer
By selecting euploid embryos, PGT-A theoretically increases the chance that a transferred embryo will successfully implant in the uterus. Some single-center studies have reported higher pregnancy rates per embryo transfer in PGT-A cycles.[2]
Reduced Miscarriage Risk
Since aneuploidy is responsible for approximately 50-70% of first-trimester miscarriages, screening out aneuploid embryos should reduce the risk of pregnancy loss.
Reduced Time to Pregnancy
By avoiding transfers of chromosomally abnormal embryos that are unlikely to succeed, PGT-A may help patients achieve a successful pregnancy faster, reducing the emotional and financial toll of multiple failed IVF cycles.
Confidence in Single Embryo Transfer (eSET)
Transferring a single euploid embryo may give patients the confidence to avoid multiple embryo transfers, thereby reducing the risks associated with twin or triplet pregnancies.
Particularly Helpful for Advanced Maternal Age
Women over 35—especially those over 40—have significantly higher rates of chromosomally abnormal embryos. PGT-A is often recommended for this group as a way to identify the rare euploid embryos among many aneuploid ones.[3]

These are compelling arguments, and they explain why PGT-A use has grown rapidly since the introduction of next-generation sequencing-based preimplantation genetic testing platforms in the mid-2010s.

So what's the problem?

The Core of the Controversy: 3 Key Criticisms of PGT-A

The controversy surrounding PGT-A is not about whether the technology works in theory. It's about accuracy in practice, the biological complexity of human preimplantation embryos, and whether the benefits outweigh the risks for all patients.

Criticism #1: The Biopsy Isn't the Whole Story

The fundamental issue: PGT-A analyzes cells from the trophectoderm—the outer layer of the blastocyst that becomes the placenta—not the inner cell mass that becomes the fetus.

The critical question: Is this small sample of 5-10 placental cells truly representative of the entire embryo?

Research suggests the answer is complicated. Embryos can exhibit chromosomal mosaicism, meaning different cells within the same embryo can have different genetic makeups. An embryo might have:

Normal cells in the inner cell mass (future baby)
Abnormal cells in the trophectoderm (future placenta)

If the PGT-A biopsy happens to sample the abnormal cells, the test will classify the embryo as "aneuploid" or "mosaic"—even though the fetus itself could be perfectly chromosomally normal.[4]

The consequence: A potentially healthy, viable embryo gets discarded or deprioritized based on cells that would have become the placenta, not the baby.

Criticism #2: Embryos Can "Self-Correct"

One of the most fascinating and controversial aspects of early embryo development is the emerging evidence that some embryos with chromosomal abnormalities can "self-correct" during development.

The theory: Embryos may have mechanisms to:

Push abnormal cells out of the developing embryo
Allow normal (euploid) cells to proliferate and dominate
Confine abnormal cells to the placenta, where they cause no harm to the fetus[5]

The evidence:

Multiple studies have documented healthy live births from embryos initially classified as "aneuploid" or "mosaic" by PGT-A[6]
Prenatal testing (CVS and amniocentesis) has confirmed normal fetal chromosomes in pregnancies that resulted from mosaic embryo transfers
Some clinics that have transferred mosaic embryos—embryos that would have been discarded under stricter protocols—have reported successful pregnancies and births

The implication: If embryos can self-correct, then PGT-A may be overestimating the number of truly non-viable embryos, leading to the unnecessary discard of embryos with reproductive potential.

Criticism #3: The High "False Positive" Rate

This is the heart of the PGT-A controversy and the source of the most emotional patient stories and legal disputes.

What is a "false positive" in this context?
A false positive occurs when PGT-A labels a healthy, viable embryo as "chromosomally abnormal." The test says the embryo won't work, but in reality, it could have resulted in a healthy pregnancy and baby.

Why does this happen?

Mosaicism: As discussed above, the biopsy may sample abnormal placental cells while missing the normal fetal cells
Technical errors: No genetic test is perfect; sequencing errors, contamination, and interpretation mistakes can occur
Biological complexity: Early embryos are chaotic, and chromosomal abnormalities at the blastocyst stage don't always predict the embryo's true developmental potential

The devastating consequence:
Patients may discard their only embryos based on PGT-A results, believing they have no chance of success. Later, they may learn—through news articles, support groups, or research studies—that those embryos might have worked.

Real-world impact: Several patients have filed lawsuits against fertility clinics and PGT-A testing companies, claiming they were not adequately informed about the test's limitations and the possibility of false positives.[1] While the legal outcomes vary, these cases highlight genuine patient harm and the need for transparent informed consent.

The "Gray Zone": What Happens to Mosaic Embryos?

Perhaps no issue better illustrates the PGT-A controversy than the question of mosaic embryos—those with an intermediate level of chromosomal abnormality (typically 20-80% abnormal cells in the biopsy).

The Evolution of Clinic Policies

Years ago: Mosaic embryos were routinely discarded. The prevailing wisdom was "abnormal is abnormal."

Today: Leading reproductive medicine societies and many fertility clinics have revised their recommendations. The American Society for Reproductive Medicine (ASRM) and the Preimplantation Genetic Diagnosis International Society (PGDIS) now acknowledge that mosaic embryos can result in healthy live births and should not be automatically discarded.[7]

Current best practice: Mosaic embryos are ranked lower than euploid embryos but may be considered for transfer after:

Extensive genetic counseling
Detailed discussion of the specific chromosome involved and the level of mosaicism
Confirmation that the patient has no euploid embryos available
Agreement to proceed with prenatal diagnostic testing during pregnancy

The Numbers

Research on mosaic embryo transfers shows:

Implantation rates: Lower than euploid embryos but not zero (approximately 40-50% vs. 55-60% for euploid embryos)[8]
Miscarriage rates: Slightly higher than euploid transfers but many result in ongoing pregnancies
Live birth outcomes: The majority of babies born from mosaic embryo transfers are chromosomally normal

What this means: Many embryos labeled "mosaic" by PGT-A have the potential to become healthy children. Discarding them without consideration may unnecessarily limit a patient's reproductive options as “true” and “false” mosaicism both have been confirmed to exist. (The "mosaic" embryo: misconceptions and misinterpretations in preimplantation genetic testing for aneuploidy (PGT-A) by Treff NR, Marin D. Fertility and Sterility, 2021.)

Summary: The PGT-A Debate at a Glance

The Promise of PGT-A	The Controversy & Criticism
Selects "best" embryo for transfer	Biopsy may not represent the whole embryo (mosaicism)
May increase implantation rate per transfer	Embryos may self-correct; abnormal cells don't always predict failure
Reduces miscarriage risk (in theory)	High false-positive rate can lead to discarding viable embryos
Reduces time-to-pregnancy by avoiding failed transfers	Limited evidence that PGT-A improves cumulative live birth rate per cycle
Enables confident single embryo transfer	Adds cost ($3,000-$7,000) with unclear benefit for many patients
Particularly helpful for advanced maternal age (>38)	May not benefit younger, good-prognosis patients

What Does the Latest Research Say?

The debate isn't just theoretical—it's backed by evolving scientific evidence.

Recent Randomized Controlled Trials

Two major randomized controlled trials published in 2021 and 2024 found:

No significant improvement in cumulative live birth rates when comparing PGT-A to conventional IVF without genetic testing in good-prognosis patients[9][10]
PGT-A may increase the live birth rate per embryo transfer, but when you account for embryos discarded due to abnormal results, the overall success rate per IVF cycle is similar

Translation: For many patients—particularly younger women with good ovarian reserve—PGT-A doesn't improve the ultimate outcome: taking home a baby.

Where PGT-A May Still Help

The evidence suggests PGT-A may be most beneficial for:

Women of advanced maternal age (38+) with high aneuploidy rates
Patients with recurrent pregnancy loss due to chromosomal issues
Couples who strongly prioritize minimizing miscarriage risk over maximizing the number of embryo transfer opportunities
Patients undergoing PGT-M (testing for single-gene disorders) who are already doing embryo biopsy

Our Approach: Navigating the PGT-A Debate with True Informed Consent

At our clinic, we believe the PGT-A controversy represents an opportunity to practice medicine differently. Rather than avoiding the uncomfortable questions, we embrace them as part of our commitment to patient-centered care.

1. We Believe in Transparency

We openly acknowledge the limitations and controversy surrounding PGT-A. This article is evidence of that commitment. No genetic test is perfect, and PGT-A is no exception. Patients deserve to know about:

The risk of false positives
The phenomenon of embryo mosaicism
The possibility of self-correction
The limited evidence for routine use in all patient populations

2. We Emphasize Genetic Counseling

A PGT-A result is not a simple "yes" or "no." We believe every patient undergoing PGT-A deserves access to a genetic counselor who can:

Explain the nuances of their specific results
Discuss the meaning of mosaicism levels and which chromosomes are involved
Present all available options, including the potential to transfer mosaic or even some aneuploid embryos
Support patients in making decisions aligned with their values

3. We Have a Nuanced Embryo Transfer Policy

Our policy is not to automatically discard mosaic embryos. Instead:

We rank embryos by predicted viability (euploid > low-level mosaic > high-level mosaic > aneuploid)
We consider transferring mosaic embryos, particularly when no euploid embryos are available
We empower patients with all available data and support them in making decisions that feel right for them
We respect that some patients may choose to transfer a "lower-potential" embryo rather than discard it

4. We Individualize Recommendations

PGT-A is not automatically recommended for every patient. We consider:

Patient age: Stronger recommendation for women 38+
Ovarian reserve: Patients producing few embryos may not benefit
History: Recurrent miscarriage or failed transfers may warrant testing
Personal values: Some patients prefer maximal information; others prefer to transfer untested embryos

The bottom line: We view PGT-A as a tool in the toolbox, not a requirement. The decision should be personalized based on your unique situation.

Key Questions to Ask Your Fertility Clinic About PGT-A

Empower yourself by asking these critical questions before deciding whether to proceed with PGT-A:

"What is your clinic's policy on transferring mosaic embryos?"
(Clinics that automatically discard mosaics may not be following current best practices)
"What is the false positive rate of the PGT-A lab you use?"
(Most labs report 5-10% error rates; some are higher)
"If I have no euploid embryos after testing, what are my options at your clinic?"
(Can you transfer mosaic embryos? Untested embryos from a repeat cycle?)
"Do I have access to a genetic counselor to discuss my PGT-A results in detail?"
(Genetic counseling should be standard, not optional)
"What does the research say about PGT-A for someone my age with my diagnosis?"
(The answer should reference recent RCTs and cumulative live birth data)
"What percentage of your patients use PGT-A, and do you recommend it for everyone?"
(Be wary of clinics that universally recommend it as a profit center)
"If my embryo is labeled aneuploid, will you allow me to transfer it if I choose?"
(Patient autonomy matters—some embryos labeled aneuploid have produced healthy babies)

Conclusion: PGT-A is a Powerful Tool, Not a Perfect Test

The PGT-A controversy highlights a critical truth that patients deserve to know: preimplantation genetic testing for aneuploidy is a powerful screening tool that provides valuable information, but it is not an infallible diagnostic test.

The risk of false positives—and the heartbreaking possibility of discarding an embryo that could have become your child—is real. So is the phenomenon of embryo mosaicism and the potential for self-correction. These are not fringe theories; they are documented in peer-reviewed research and acknowledged by leading reproductive medicine organizations.

Does this mean PGT-A is bad? No. For some patients—particularly those of advanced maternal age or with specific medical histories—PGT-A can be genuinely helpful in selecting the embryo most likely to result in a healthy pregnancy.

What it does mean is that PGT-A should not be presented as a one-size-fits-all solution or a guaranteed path to success. The decision to use PGT-A must be made thoughtfully, with full informed consent, and with a clinic that:

Acknowledges the limitations of the test
Provides access to genetic counseling
Has a flexible policy on mosaic embryos
Respects patient autonomy in the face of uncertain results

The most important step is choosing a fertility clinic that engages in this conversation openly and honestly—one that sees you as a partner in your care, not a passive recipient of recommendations.

If you're navigating the PGT-A decision and want a clinic that prioritizes transparency and individualized care, we're here to help.

Schedule a Consultation to Discuss Your PGT-A Options

Frequently Asked Questions

Is PGT-A worth the cost?

This depends entirely on your individual situation. For women under 35 with good ovarian reserve, recent research suggests PGT-A may not improve cumulative live birth rates and may not be cost-effective. For women over 38 or those with recurrent pregnancy loss, the calculus may be different. Discuss your specific risk-benefit profile with your doctor.

Can I trust my PGT-A results?

PGT-A is highly accurate for detecting whole-chromosome aneuploidies, but it's not perfect. The test has a ~5-10% false positive rate, and mosaic results are particularly difficult to interpret. It's a screening test, not a diagnostic test. If you're uncertain about your results, request genetic counseling and consider the possibility of transferring embryos classified as mosaic or even aneuploid if no other options exist.

What if all my embryos came back abnormal?

First, don't panic. This is a devastating result, but it doesn't necessarily mean none of your embryos would have worked. Options include:

Discussing mosaic embryo transfer with your doctor and genetic counselor
Pursuing another IVF cycle without PGT-A
Getting a second opinion or re-biopsy (if embryos remain frozen)
Considering whether PGT-A was truly indicated for your situation

Are mosaic embryos dangerous to transfer?

No, transferring a mosaic embryo does not pose a safety risk. The concern is about efficacy (will it work?) not safety. Most mosaic embryos either fail to implant or result in chromosomally normal pregnancies. The risk of having a baby with a chromosomal abnormality from a mosaic embryo is low, but prenatal diagnostic testing (amniocentesis) is recommended to confirm fetal health.

Why do some clinics still automatically discard mosaic embryos?

Clinic policies vary widely, and not all have updated their practices to reflect current research. Some clinics may be following outdated guidelines, while others may be overly cautious about medical-legal risk. This is why asking about mosaic embryo policies is so important when choosing a fertility clinic.

Is there an alternative to PGT-A?

Yes—you can proceed with IVF without embryo genetic testing and select embryos for transfer based on morphology (appearance) alone, which is what was done for decades before PGT-A existed. Many patients still conceive healthy babies this way. The trade-off is that you may experience more failed transfers or miscarriages, but you won't risk discarding viable embryos based on testing.

Can PGT-A detect all genetic problems?

No. PGT-A only screens for chromosome number (aneuploidy). It does not detect single-gene disorders, structural chromosomal rearrangements, or other genetic problems. Even with PGT-A, standard prenatal testing during pregnancy is still recommended.

Scientific References

[1] Stein, R. (2021). "Some Couples Are Suing Over Faulty Embryo Genetic Tests." TIME Magazine.
https://time.com/6092368/ivf-embryo-genetic-testing-lawsuits/

[2] Practice Committees of the American Society for Reproductive Medicine and Society for Assisted Reproductive Technology. (2024). "The use of preimplantation genetic testing for aneuploidy: a committee opinion." Fertility and Sterility, 122(3), 421-434.
https://www.asrm.org/practice-guidance/practice-committee-documents/the-use-of-preimplantation-genetic-testing-for-aneuploidy-a-committee-opinion-2024/

[3] Franasiak, J.M., Forman, E.J., Hong, K.H., et al. (2014). "The nature of aneuploidy with increasing age of the female partner: a review of 15,169 consecutive trophectoderm biopsies." Fertility and Sterility, 101(3), 656-663.
https://pubmed.ncbi.nlm.nih.gov/24355045/

[4] Capalbo, A., Poli, M., Rienzi, L., et al. (2021). "Mosaic human preimplantation embryos and their developmental potential in a prospective, non-selection clinical trial." American Journal of Human Genetics, 108(12), 2238-2247.
https://www.cell.com/ajhg/fulltext/S0002-9297(21)00412-2

[5] Taylor, T.H., Gitlin, S.A., Patrick, J.L., et al. (2014). "The origin, mechanisms, incidence and clinical consequences of chromosomal mosaicism in humans." Human Reproduction Update, 20(4), 571-581.
https://pubmed.ncbi.nlm.nih.gov/24634322/

[6] Victor, A.R., Griffin, D.K., Brake, A.J., et al. (2019). "Assessment of aneuploidy concordance between clinical trophectoderm biopsy and blastocyst." Human Reproduction, 34(1), 181-192.
https://pubmed.ncbi.nlm.nih.gov/30481316/

[7] Practice Committee and Genetic Counseling Professional Group of ASRM. (2023). "Clinical management of mosaic results from preimplantation genetic testing for aneuploidy: a committee opinion." Fertility and Sterility, 120(5), 973-982.
https://www.asrm.org/practice-guidance/practice-committee-documents/clinical-management-of-mosaic-results-from-preimplantation-genetic-testing-for-aneuploidy-pgt-a-of-blastocysts-a-committee-opinion/

[8] Viotti, M., Victor, A.R., Barnes, F.L., et al. (2021). "Using outcome data from one thousand mosaic embryo transfers to formulate an embryo ranking system for clinical use." Fertility and Sterility, 115(5), 1212-1224.
https://pubmed.ncbi.nlm.nih.gov/33641774/

[9] Yan, J., Qin, Y., Zhao, H., et al. (2021). "Live birth with or without preimplantation genetic testing for aneuploidy." New England Journal of Medicine, 385(22), 2047-2058.
https://www.nejm.org/doi/full/10.1056/NEJMoa2103613

[10] Munné, S., Kaplan, B., Frattarelli, J.L., et al. (2019). "Preimplantation genetic testing for aneuploidy versus morphology as selection criteria for single frozen-thawed embryo transfer in good-prognosis patients: a multicenter randomized clinical trial." Fertility and Sterility, 112(6), 1071-1079.
https://www.fertstert.org/article/S0015-0282(19)31979-X/fulltext