PGS VS. PGD IN SURROGACY: WHICH GENETIC TEST IS BEST FOR YOUR EMBRYOS?

When you’re pursuing surrogacy through IVF, you may hear terms like PGS, PGD, PGT-A, PGT-M, or PGT-SR during your IVF process. These tests are designed to give your fertility team more information about your embryos before transfer, but they’re not all used for the same reason. For intended parents working with a surrogate, understanding the difference can help you feel more prepared as you move through IVF, embryo creation, genetic counseling, and transfer planning.

Understanding the difference between PGS and PGD matters because embryo testing can influence which embryos are considered for transfer, when a transfer cycle may be scheduled with your gestational surrogate, and how your fertility clinic, care team, and agency coordinate next steps. We’ll also look at where genetic carrier screening comes in before embryo creation, when intended parents may need one type of testing or both, how the testing process works, and what to understand about success rates, limitations, risks, and cost before making a decision with your fertility team.

What PGS and PGD Test For and Why the Names Have Changed

Historically, intended parents often heard two main terms: PGS and PGD.

PGS, or preimplantation genetic screening, refers to testing that assesses whether an embryo has the expected number of chromosomes. This type of testing screens for aneuploidy, when an embryo has too many or too few chromosomes. Today, this is more commonly called PGT-A, or preimplantation genetic testing for aneuploidy. The American College of Obstetricians and Gynecologists explains that PGT-A screens embryos for whole chromosome abnormalities before transfer.

PGD, or preimplantation genetic diagnosis, was used when testing embryos for a known inherited genetic condition or single-gene disorder. Today, this is typically called PGT-M, or preimplantation genetic testing for monogenic conditions. The American Society of Reproductive Medicine describes PGT-M as testing used for monogenic, or single-gene, conditions and emphasizes the importance of counseling around its clinical and technical complexities.

You may also hear the term PGT-SR, which refers to preimplantation genetic testing for structural rearrangements. This may be considered when a biological parent has a known chromosomal rearrangement, such as a balanced translocation.

In simple terms:

• PGT-A looks at chromosome number.

• PGT-M looks for a specific inherited gene mutation.

• PGT-SR looks for certain structural chromosome issues.

While many people still use PGS and PGD conversationally, most clinics and genetic testing laboratories now use the updated PGT terminology.

Where Genetic Carrier Screening Fits Before Embryo Testing

Before embryo testing is considered, intended parents, egg donors, and sperm donors may complete genetic carrier screening, a step that's distinct from testing the embryos themselves.

Carrier screening examines whether people contributing eggs or sperm carry genetic variants that could be passed on to a child. These may include autosomal recessive conditions, autosomal dominant conditions, and X-linked conditions. Genetic counseling for PGT is commonly used in cases involving autosomal dominant, autosomal recessive, and sex chromosome-linked disorders.

This step matters because many carriers are healthy and have no symptoms. If both genetic contributors are carriers for the same autosomal recessive condition, or if there is a known inherited condition in the family, a genetic counselor may recommend PGT-M. This is also relevant for intended parents who are using both an egg donor and a sperm donor, a situation common among single intended parents and many LGBTQIA+ families, where carrier screening helps assess compatibility between donors before embryos are created. In those cases, the laboratory may design a customized test to look for that specific gene mutation in embryos before transfer.

For intended parents using an egg donor, sperm donor, or both, carrier screening can also help your care team assess compatibility before embryos are created. The goal is to identify risks early enough to make informed decisions.

When Intended Parents Need PGS, PGD, or Both

The right testing depends on your medical history, family history, age, and the genetic contributors involved.

PGT-A, formerly called PGS, may be discussed when the person contributing eggs is over 35 or between the ages of 38 and 41. As egg age increases, the likelihood of chromosomal abnormalities in embryos also increases, which can affect implantation, miscarriage risk, and the number of embryos available for transfer. ASRM’s 2023 committee opinion reviews the use of PGT-A and notes that its effectiveness can vary by patient population and clinical context.

PGT-M, formerly called PGD, may be recommended when there’s a known gene mutation, a family history of genetic disease, or carrier screening results that show a risk for a specific inherited condition. ASRM notes that PGT-M has become more complex and more frequently used as embryo biopsy and DNA technologies have advanced.

Some intended parents may use both PGT-A and PGT-M. For example, if embryos are being tested for a specific inherited disorder, the same embryo biopsy may also be used to assess chromosome number. 

Genetic testing is especially valuable in identifying chromosomally normal embryos pre-transfer. Identifying embryos with the strongest likelihood of implantation may help support a more efficient transfer plan, though no test can guarantee a pregnancy.

How Preimplantation Genetic Testing Works

Preimplantation genetic testing happens during an IVF cycle before an embryo is transferred to a surrogate.

After eggs are retrieved and fertilized, embryos are monitored as they develop in the embryology lab. Testing is performed at the blastocyst stage, often around days 5 through 7 of embryo development. At that point, an embryologist removes a small number of cells from the part of the embryo that is expected to become the placenta. The embryo is usually frozen while the sample is sent to a genetic testing laboratory.

At the laboratory, the testing depends on what has been ordered. For PGT-A, the lab analyzes chromosome number. For PGT-M, the lab looks for a specific gene mutation or inherited condition. For PGT-SR, the lab evaluates specific chromosomal structural concerns.

The results are then sent back to the fertility clinic and reviewed with the intended parents, often alongside a reproductive endocrinologist and genetic counselor. Many clinics quote a turnaround time of roughly 1 to 2 weeks for PGT results, though timing can vary by laboratory, test type, batching, and whether a customized PGT-M probe must be created.

This timeline is important to intended parents because it may affect when the embryo transfer cycle can be scheduled with the surrogate.

How Genetic Testing Affects Transfer Success

One of the main reasons intended parents consider PGT-A is to help identify euploid embryos, meaning embryos with the expected number of chromosomes. In many studies, euploid embryos are generally more likely to implant and less likely to result in miscarriage than embryos with significant chromosomal abnormalities.

Research on PGT-A continues to evolve, and results can depend on patient age, embryo quality, testing technology, and study design. A Fertility and Sterility review on euploid blastocyst implantation emphasizes that even when a euploid embryo is transferred, implantation depends on many additional factors, including embryo characteristics, endometrial receptivity, uterine factors, and clinical protocol.

For intended parents, this means genetic testing is only one part of the larger picture. The reproductive endocrinologist’s protocol, embryo quality, the surrogate’s medical screening, uterine health, medication response, and overall coordination of care all play important roles. At its best, PGT-A helps your care team choose embryos with stronger transfer potential.

Risks and Limitations of Embryo Genetic Testing

It's worth understanding the limitations of embryo genetic testing before making decisions.

First, embryo biopsy is a highly specialized procedure that involves removing cells from an embryo. Many embryos tolerate biopsy and freezing well, but there can be embryo survival implications depending on embryo quality, lab technique, and thaw outcomes.

Second, results are not always simple. Some embryos may come back as mosaic, meaning the biopsy shows a mixture of normal and abnormal cells. Mosaic results can complicate transfer decisions because the biopsy reflects only the sampled cells, not necessarily every cell in the embryo. ASRM has separate guidance addressing the clinical management of mosaic results after PGT-A.

Third, PGT-A may reduce the number of embryos available for transfer if embryos are reported as aneuploid or abnormal. This can be challenging, especially for intended parents with a smaller embryo cohort.

Finally, genetic testing cannot guarantee a positive pregnancy, a live birth, or a child without medical conditions. The American College of Obstetricians and Gynecologists notes that traditional diagnostic testing or screening during pregnancy may still be offered even after preimplantation genetic testing.

This is why genetic counseling is so important. A genetic counselor can help you understand what the test can tell you, what it cannot tell you, and how the results may shape your next steps. These results can raise difficult questions, and working through them with a genetic counselor is an important part of the process. 

What PGS and PGD Cost and How to Plan

The cost of embryo genetic testing varies widely by clinic, laboratory, location, number of embryos tested, and type of testing.

In general, PGT-A, formerly PGS, may cost several thousand dollars per IVF cycle. Some published fertility cost estimates list PGT or PGT-A costs in the range of about $3,000 to $7,000 per cycle, though national pricing can vary significantly.

PGT-M, formerly PGD, is often more expensive because it may require custom test development for a specific gene mutation or family variant. Some current fertility cost resources estimate PGT-M at about $7,000 to $12,000 per IVF cycle, depending on the laboratory, clinic, and the number of embryos tested.

Costs may include a few separate pieces:

• The embryo biopsy fee, charged by the embryology lab or fertility clinic.

• The genetic testing fee, often charged by the testing company.

•  A per-embryo fee, depending on the lab’s pricing model.

•  A set-up or probe development fee, especially for PGT-M.

•  Possible shipping, courier, cryopreservation, or storage fees.

Some laboratories offer a flat rate for testing up to a set number of embryos, while others charge per embryo. These fees are usually separate from the IVF cycle itself and may be paid out of pocket, depending on insurance coverage and medical indication.

Your best approach as an intended parent is to ask your fertility clinic for a written estimate that separates IVF costs, biopsy fees, PGT-A or PGT-M fees, embryo freezing, storage, and transfer costs. 

Frequently Asked Questions

Can you do PGS and PGD on the same embryo?

Yes. In many cases, the same embryo biopsy can be used for both chromosome screening and testing for a specific inherited condition. In updated terminology, this means PGT-A and PGT-M may be performed together. 

How long does genetic testing take on embryos?

Many PGT-A results are returned in about 1 to 2 weeks, although timing varies by clinic and lab. PGT-M can take longer if the lab must first create a customized test for a specific gene mutation. Your fertility clinic and genetic counselor can give you the most accurate timeline based on your test type and IVF cycle plan. 

Does genetic testing damage the embryo?

Embryo biopsy is commonly performed at experienced IVF laboratories, and many embryos survive biopsy, freezing, thawing, and transfer. However, it’s still a procedure performed on an embryo, and there are risks. Embryo quality, laboratory experience, freezing and thawing protocols, and the number of cells removed can all matter. This is one reason PGT should be discussed carefully with your reproductive endocrinologist and genetic counselor. 

Is PGT-A recommended for all IVF cycles in surrogacy?

Not always. PGT-A may be especially relevant when the egg provider is older, when there's a history of prior pregnancy loss or failed transfers, or when intended parents want additional information before selecting an embryo for transfer. 

What are the potential benefits, risks, and limitations of PGS and PGD for intended parents?

The potential benefits include better embryo selection, reduced risk of transferring embryos with certain chromosomal abnormalities, and the ability to avoid transferring embryos affected by a known inherited condition. For intended parents, this supports a more informed and coordinated transfer plan.

The risks and limitations include added cost, embryo biopsy considerations, possible mosaic or inconclusive results, fewer embryos available for transfer, and the emotional weight of deciding what to do with abnormal or uncertain results. Most importantly, PGT does not guarantee implantation, pregnancy, live birth, or a child free of all medical conditions.

Genetic testing decisions are made in close partnership with your fertility clinic, reproductive endocrinologist, genetic counselor, and care team. At Growing Generations, our team has supported intended parents through thousands of IVF and transfer cycles, and we understand how much is at stake at this stage. We work closely with your fertility clinic to help coordinate timing, information, and next steps — so you're not navigating this alone. To learn more, explore our intended parents overview or schedule a consultation with our team.