Should I Only Transfer a “Perfect” Embryo? What Surrogates Need to Know About PGT-Testing

If you have spent any time in surrogate Facebook groups, you have probably come across some version of this advice: only agree to carry a tested euploid embryo. It circulates so frequently that many first-time gestational carriers (surrogates) assume it is standard practice, or even a requirement. It is not, and the science is more nuanced than the forums suggest.

As Founder and Executive Director of Brownstone Surrogacy, I work closely with surrogates, intended parents, and medical professionals to make sure the people in our care have access to accurate, thoughtful information, not just the advice that happens to be trending online. Discussions at the 2026 SEEDS Conference (Society for Ethics in Egg Donation and Surrogacy) highlighted the growing gap between what surrogates are hearing in peer communities and what reproductive medicine actually tells us about embryo quality and genetic testing. This piece is my attempt to bridge that gap.

One place that gap shows up most practically is in the matching process itself.

Finding the right match is already a carefully considered process. The right agency will take the time to understand who you are and what you need, matching you not only on logistics, but the things that make a journey feel right. That includes the intended parents’ family structure, their communication style and how often you want to stay in touch (during the journey and after delivery), geographic proximity if that matters to you, shared values around the journey itself and much more. The goal is to find people you actually want to go on this journey with. 

All of these factors shape your pool of potential matches, and that is exactly how it should be. Adding a firm requirement around embryo testing narrows that search further. In most cases it may not change much, but in some situations, it can mean a longer road to finding your match, without necessarily improving your odds of a successful pregnancy. The rest of this article explains why.

PGT (Preimplantation Genetic Testing) is a group of genetic tests performed on embryos before they are transferred to a uterus during IVF. According to the American College of Obstetricians and Gynecologists (ACOG), there are three main types, each testing for something different. The embryo testing most commonly used in surrogacy is PGT-A, which screens embryos for chromosomal abnormalities. Embryos that test as chromosomally normal are called “euploid.” Those that show abnormalities are called “aneuploid.

It is important to know that no PGT result is a guarantee. ACOG notes that false-positive and false-negative results are possible, meaning a “normal” result does not ensure a baby without genetic abnormalities.

A mosaic embryo falls somewhere in between euploid and aneuploid. ACOG defines it as an embryo containing a mix of chromosomally normal and abnormal cells. Mosaic embryos were historically not considered for transfer, but research has shown that healthy babies can be born from them. Transferring a mosaic embryo requires detailed counseling and is a decision made in close consultation with a reproductive specialist.

Where the “euploid embryos only” myth comes from:

Finding reliable, accessible information about surrogacy is difficult. Medical literature is dense and often paywalled. Clinic websites vary widely in what they share. The surrogacy process involves so many moving parts that even well-informed surrogates can find themselves with more questions than answers. Online communities fill that gap. Surrogates show up for one another in these spaces with generosity and compassion, sharing their experiences, their fears, and the lessons they have learned the hard way. That peer support is real and valuable, and for many surrogates it is the most accessible resource they have. Advice that worked for one surrogate in one situation gets shared and reshared until it starts to sound like a rule. Surrogates are trying to protect themselves and each other, and that instinct is entirely reasonable—it also, inevitably, ends up missing some nuance.

A surrogate’s journey involves far more than the transfer itself. In the months leading up to it, the surrogate undergoes a demanding IVF medication protocol, coordinating appointments, injections, and their own family’s schedule around a process that is physically and emotionally taxing. A failed transfer does not just mean disappointment. It means restarting that entire process, sometimes more than once, adding months or even years to a journey.

The stakes feel even higher when you consider what a pattern of failed transfers can mean for a surrogate’s future. Some agencies, intended parents, or clinics may choose not to continue working with a surrogate after multiple unsuccessful attempts. If a surrogate finds themself looking for a new match, a history of failed transfers may give others pause, even when those failures had nothing to do with the surrogate’s health or their body.

When a surrogate asks about embryo quality, or sets expectations about the type of embryo they are willing to carry, they are not being unreasonable. The surrogate is trying to preserve their ability to complete the journey they committed to. Any honest conversation about PGT testing has to start by acknowledging this context.

What the experts are actually saying:

Understanding why surrogates feel strongly about embryo testing requires understanding what testing actually does, and what it does not do.

PGT-A is now widely used. According to Society for Assisted Reproductive Technology (SART) data cited in a 2025 review, PGT was performed in more than 233,000 IVF cycles, compared to roughly 183,000 cycles that did not use it (Munné & Anomaly, Journal of Human and Clinical Genetics, 2025). As researchers writing in the Journal of Human and Clinical Genetics note, the procedure is now considered standard of care in many practices. The same data suggests that testing was associated with preventing approximately 15,000 miscarriages, with an additional 11,000 potentially avoidable had more cycles used PGT. That is a significant part of why many reproductive endocrinologists, including many we work with at Brownstone, generally recommend testing. 

At the same time, the American College of Obstetricians & Gynecologists (ACOG) has stated that there is currently insufficient evidence to recommend the routine use of PGT-A in all patients. PGT-A tests cells taken from the part of the embryo that will become the placenta, not the part that becomes the baby. Because of this, the results do not always reflect the full genetic picture of the embryo itself. False positives and false negatives are both possible. The test also cannot detect every type of genetic abnormality, including mutations that develop after the biopsy is taken. A normal result is genuinely good news, but it is not a guarantee of a successful pregnancy (ACOG Committee Opinion No. 799, 2020).

Research suggests that the benefit of testing is strongest for women over 35 or those with a history of failed transfers or recurrent miscarriage. In surrogacy, however, most intended parents are working with embryos created using donor eggs. Egg donors are rigorously screened, typically under 35, and have no history of failed transfers or recurrent pregnancy loss. Most surrogacy matches do not fit the profile where testing makes the biggest difference.

The recently released 2024 SART data puts additional numbers behind that point, drawing from over 430,000 egg retrieval and embryo transfer cycles across IVF clinics in the US. When looking specifically at frozen, genetically tested day 5 or 6 embryos, live birth rates for transfers back to the patient run between 54 and 58%. When that same embryo is transferred to a gestational carrier or gestational surrogate instead, live birth rates rise to just over 60%, roughly a 10% improvement, and 90% of those babies are born at full term. The data also shows that for women under 35 using their own eggs, there is only a small benefit to PGT testing. The larger benefit, where live birth rates roughly double with testing, applies to women over 40. Egg donors are young and healthy by design. Testing matters most for patients who are not. (SART, 2024 Retrieval and Transfer Tables)

None of this is an argument against testing. Testing has real benefits, and the data supports recommending it in some cases but not all. For a surrogate considering whether to require tested embryos as a condition of matching, the data is worth sitting with and discussing with your agency. Surrogates, as a group, are already behind some of the strongest IVF success rates in the dataset. The odds are genuinely in your favor.

Want to see me walk through the full SART data? I broke it down in a two-part series on Instagram. Part 1 covers overall IVF success rates. Part 2 dives into surrogacy and donor egg outcomes specifically.

Testing is just one part of how embryos are assessed before transfer. Embryo quality is another, and the data there is also more encouraging than most people expect.

Not all embryos look the same under a microscope. Embryologists grade embryos at the blastocyst stage, typically day 5 or 6 of development, based on how well they have expanded and the quality of the cells that will become the baby and the placenta (Remembryo, “Complete Guide to Embryo Grading and Success Rates”). The resulting grade gives clinicians a sense of an embryo’s quality before transfer.

Research on blastocyst grading suggests that even lower quality embryos have meaningful success rates. Live birth rates for good quality embryos run around 47%, while fair quality embryos come in around 39%, and even poor quality embryos show approximately 34%. A 13 percentage point difference is worth knowing, but it is not the dramatic drop most people imagine when they hear “poor quality embryo.” Notably, miscarriage rates were statistically similar across all quality grades (Remembryo, “Complete Guide to Embryo Grading and Success Rates”). 

A large multicenter study published in the peer-reviewed journal Fertility and Sterility (Viotti et al., 2023) analyzed outcomes from embryos classified as mosaic by PGT-A. The study found that among pregnancies that were achieved, mosaic embryos carried a higher miscarriage rate than euploid embryos: 22.2% compared to 8.9% for euploid. A 22.2% miscarriage rate is higher than we would like, but it is also a 77.8% success rate, and that number deserves equal airtime. 

The study’s findings on babies born from those successful mosaic transfers are equally encouraging. In most pregnancies, the mosaicism detected in the embryo simply resolved on its own and did not carry through to the baby. The data backs that up. Infants born from mosaic transfers were similar to infants born from euploid transfers in birth weight, length of gestation, and incidence of birth defects. Out of 488 babies born from mosaic transfers, only one had overt abnormalities. Of 250 pregnancies from mosaic transfers that underwent prenatal testing, only three showed chromosomal results matching the original mosaic finding, a rate of 1.2%.

Most surrogacy journeys end exactly the way everyone hopes, whether the embryo was tested or untested, mosaic or euploid: a healthy baby, a healthy surrogate, and a family made whole.

How a good agency guides a surrogate through this: