IVF Genetic Testing: PGT-A, PGT-M, and PGT-SR

There are three types of preimplantation genetic testing (PGT) with distinct purposes. PGT-M and PGT-SR look for a specific inherited condition a family already knows about. PGT-A screens every embryo for chromosome problems. It’s also the most contested and the one most patients are offered. The evidence doesn’t support the promise it’s usually sold on, but the test is still useful for some patients for reasons unrelated to better odds.

Test	What it checks	Who it’s for	Evidence
PGT-Aformerly PGS	Whether an embryo has the right number of chromosomes	Offered broadly, often to everyone doing IVF	ContestedASRM says its value as a routine screen has not been demonstrated. The UK regulator rates it red.
PGT-Mformerly PGD	Whether an embryo inherited one specific condition, such as cystic fibrosis, sickle cell disease, Huntington’s disease, or Tay-Sachs	Families with a known inherited condition	SettledAnswers a specific question about a known risk. Its use is not disputed.
PGT-SRformerly PGD	Whether an embryo has too little or too much genetic material, caused by a parent whose chromosomes are rearranged	People who carry a chromosome rearrangement, usually found after repeated miscarriage	SettledAnswers a specific question about a known risk. Its use is not disputed.

How the testing works

All three use the same procedure. Around day 5 or 6 when an embryo has divided into a blastocyst, an embryologist removes a few cells from the outer layer that would become the placenta. The embryo is frozen while the sample goes to a genetics lab. Results come back in 1-3 weeks, and only then does a transfer get scheduled.

Testing also means a frozen transfer in a later cycle, not a fresh one.

PGT-M and PGT-SR

If a family carries a known genetic condition such as cystic fibrosis, Huntington’s disease, sickle cell, Tay-Sachs, then PGT-M can identify which embryos inherited it. The test is built specifically for that family, using DNA from parents and often relatives. This often takes weeks to set up before a cycle can start.

PGT-SR does the same for people who carry a balanced chromosome rearrangement, where genetic material has been swapped or flipped without anything being lost. Carriers are usually healthy but can produce embryos with missing or duplicated material, which often causes miscarriage.

Neither of these is a screening test. Both answer a specific question about a known risk, and nobody seriously disputes their use.

PGT-A

PGT-A checks whether embryos have the correct number of chromosomes. Clinics often sell it on the promise that transferring only chromosomally normal embryos raises the odds of a live birth. The evidence doesn’t support that promise, but the test is still useful for some patients for reasons unrelated to better odds.

PGT-A doesn’t create more embryos or change the ones you have. It sorts them. Your cumulative success rate depends on how many viable embryos you have. Setting aside embryos flagged as abnormal can’t raise those odds, though it can lower them.

The largest trial published in the New England Journal of Medicine in 2021 followed 1,212 women aged 20 to 37 with several good-quality embryos and found that not testing worked at least as well, with a slightly higher cumulative live birth rate of 81.8% compared to 77.2%. SART registry data covering more than 133,000 cycles links PGT-A to lower cumulative live birth at younger ages, partly because viable embryos get set aside. ASRM’s 2024 committee opinion, which replaced its 2018 version, states that the evidence doesn’t support routine PGT-A for improving the chance of a baby. A 2026 Lancet review measuring live birth specifically found no clear benefit.

The HFEA, the UK’s fertility regulator, cautions that PGT-A may lower the overall chance of a baby for most patients while rating it more favorably for two narrower aims: reducing miscarriage, and reducing the chance of a baby born with a chromosomal condition.

Not transferring an embryo that was never going to work spares a failed transfer and the miscarriage that might have followed. For older patients, where most embryos are abnormal, that can mean fewer futile cycles. So it’s reasonable to consider PGT-A. It just isn’t the better odds it’s usually sold as.

Mosaic results

Some embryos come back neither normal nor abnormal. A mosaic result means the sample contained a mix of cells, which clinics routinely discarded.

However in 2015, an Italian team transferred 18 mosaic embryos — 12 didn’t result in a birth but the remaining 6 resulted in babies born at term, each confirmed by prenatal testing to have normal chromosomes. The findings established that a mosaic label doesn’t mean an embryo can’t produce a healthy child.

How often mosaic results appear varies enormously between labs. An analysis of the STAR trial data found laboratories that reported mosaicism labeled 33% to 72% of embryos abnormal, while laboratories that didn’t report mosaicism labeled 0% to 43% abnormal, in the same age group and same kind of embryos. A spread that wide means the verdict isn’t being read cleanly off the biology. It reflects where each lab draws the line between normal, mosaic, and abnormal.

If a clinic reports a mosaic result, ask what its policy is on transferring those embryos. And ask before the cycle rather than after.

PGT-A also reveals sex

PGT-A counts all 23 pairs of chromosomes, and the 23rd pair is the sex chromosomes. So every report says whether each embryo is XX or XY. No separate test, no extra cost. The information arrives as a byproduct.

Anyone doing PGT-A will learn the sex of their embryos unless they specifically ask not to be told. Wanting to know or not is a personal decision, and once you know, it typically becomes a factor in choosing which embryo to transfer whether or not that was ever the intention. So it’s worth a discussion before the results come back rather than after.

Sex selection

Because PGT-A produces the information anyway, choosing an embryo by sex requires no extra procedure.

In the United States, no state prohibits this and most clinics offer it for nonmedical reasons. ASRM’s own position is that practitioners have no ethical obligation either way to provide it or refuse. Clinics set their own policies, so this varies by clinic rather than by law.

Internationally, the US is an outlier. Canada and much of Europe ban nonmedical sex selection, and one review counted 31 countries prohibiting it for social reasons. Some countries allow sex selection only when a family already has multiple children of the same sex. In some other countries, sex selection is the most common reason patients pursue PGT-A at all.

The practical version of this decision is narrower than the debate around it though. For instance someone with two viable embryos, one of each sex, is choosing between the only two options they have.

What it costs

PGT is billed in two parts: a fee from the clinic for the biopsy, and a separate fee from the genetics lab for the analysis. The lab fee is usually charged per embryo, so the total scales with how many embryos get tested. Here are typical total costs per cycle:

PGT-A — $3,000 to $6,000

PGT-SR — $5,000 to $10,000

PGT-M — $7,000 to $12,000

PGT-A is cheapest because it’s the same test for everyone, though prices for it vary widely between clinics.

PGT-SR and PGT-M cost more because a custom test has to be built for each patient’s specific rearrangement or mutation.

Roughly 95% of insurance plans exclude PGT even when they cover IVF.

The cost that’s not in the quote

Results can take 1-3 weeks to return and embryos must be frozen to stay viable during that time frame. So every PGT cycle forces a frozen transfer later in a separate cycle. Anyone who was thinking of having a fresh transfer in the same cycle is now paying for an additional procedure.

That commits two costs beyond the testing: freezing (about $1,000 to $2,000) and a frozen embryo transfer (about $3,000 to $6,000).

Questions to ask

Which test are they recommending, and what is specifically prompting the recommendation?
What will this cost in total, including the freezing and the frozen transfer?
What does this clinic do with mosaic results?
What happens if testing leaves no transferable embryos?

Bottom line

If a known genetic condition runs in the family, PGT-M and PGT-SR test for something specific, and the evidence supports them. PGT-A is different. It’s routinely offered, expensive, and neither the US professional society nor the UK regulator finds it improves the chance of a baby as a general screen. That doesn’t make it useless for every patient. It does mean the burden is on the clinic to explain why it applies to you.

Related reading

Can You Ask for Twins with IVF?

How Conception Works, and Where IVF Steps In

Sex Selection with IVF

How Long Does IVF Take?