PGT-A & PGD embryo testing

Preimplantation genetic testing (PGT) is a laboratory check carried out on embryos created during IVF (in vitro fertilisation), before any embryo is transferred to the womb. The idea is simple: a few cells are gently taken from each embryo and examined in a genetics lab, so the team can choose which embryo to transfer based on its chromosomes or genes, not just how it looks under the microscope.

There are three related tests, and the names can be confusing, so here they are in plain words:

• PGT-A (preimplantation genetic testing for aneuploidy) checks whether an embryo has the right number of chromosomes. "Aneuploidy" simply means a missing or extra chromosome. An embryo with the correct count is called euploid; one with the wrong count is aneuploid. This test used to be called PGS (preimplantation genetic screening).
• PGT-M (testing for monogenic disorders) looks for a single specific gene fault that runs in the family, such as cystic fibrosis or sickle cell disease. This is what people traditionally called PGD (preimplantation genetic diagnosis).
• PGT-SR (testing for structural rearrangements) is for people who carry a known rearrangement of chromosome pieces, such as a translocation, where parts of two chromosomes have swapped places.

Chromosomes are the tightly packed bundles of DNA inside each cell; most people have 23 pairs. Genes are the individual instructions written along those chromosomes. PGT-A counts the bundles; PGT-M reads one specific instruction; PGT-SR checks that the bundles are arranged correctly. None of these tests is a treatment in itself — they are a way of choosing among embryos you already have.

Embryo testing is added on to an IVF cycle, so the first requirement is simply that you are going through IVF. Beyond that, the three tests suit different situations.

PGT-A is most often discussed for:

• Women in their late 30s and 40s, because the chance of an embryo having the wrong number of chromosomes rises naturally with the egg's age.
• People who have had several miscarriages.
• People who have had repeated IVF transfers that did not lead to pregnancy.

It is important to be honest about the evidence here. According to the UK fertility regulator (the HFEA), there is no good evidence from high-quality trials that PGT-A improves the overall chance of having a baby for most IVF patients, although some evidence suggests it may lower the miscarriage rate, particularly in older women or those with a history of miscarriage. PGT-A is a selection tool, so it can also leave you with fewer embryos to transfer. It is a personal decision to weigh with your doctor, not an automatic upgrade.

PGT-M (PGD) is for couples with a known, documented single-gene condition in the family — for example one partner carries a faulty gene, or both partners carry the same recessive fault. Typical reasons include serious childhood conditions such as Tay-Sachs disease, cystic fibrosis, sickle cell disease and spinal muscular atrophy, and some serious adult-onset conditions such as Huntington disease or inherited cancer risk (for example BRCA gene faults).

PGT-SR is for people who are known to carry a chromosomal rearrangement and are therefore at higher risk of miscarriage or of a baby with a chromosome disorder.

Who should think twice or avoid it: if you have very few embryos, testing can sometimes leave you with none suitable to transfer, even though an untested embryo might have led to a healthy pregnancy. Professional bodies (such as ASRM) do not recommend PGT-M simply to check healthy carrier status for a recessive condition, or for non-medical reasons. Using PGT to choose a baby's sex for social (non-medical) reasons is not allowed in Turkiye.

All three tests share the same first step — taking a small sample of cells from the embryo (a biopsy) — but they differ in what the laboratory then looks for.

PGT-A: counting chromosomes

The lab uses a method called next-generation sequencing (NGS) to read the embryo's DNA and work out whether each chromosome is present in the normal amount. It reports each embryo as euploid (normal count), aneuploid (abnormal count), or sometimes mosaic — meaning the sample contained a mix of normal and abnormal cells.

PGT-M / PGD: reading one gene

Here the lab is hunting for one specific, known gene fault. Because a tiny sample of DNA can occasionally give a misleading reading, labs usually combine two approaches: direct analysis (looking straight at the known fault) and linkage analysis (tracking harmless DNA markers that sit next to the fault and are inherited along with it). Combining both reduces the risk of a wrong call. PGT-M is custom-built for each family, so the lab usually needs DNA samples from the parents — and sometimes relatives — to set up the test before the IVF cycle.

PGT-SR: checking the arrangement

This test confirms whether the embryo has inherited a balanced (workable) set of chromosomes or an unbalanced one from a parent who carries a rearrangement. It also generally uses NGS or related techniques.

About mosaicism: a "mosaic" result means the cells sampled were not all the same. Mosaic embryos may have a lower chance of success, yet healthy babies have been born from them, and clinics differ in how they handle such results. This is one reason a genetic counsellor's input matters.

Embryo testing is woven into a normal IVF cycle, so the steps below describe the whole journey, with the testing slotted in.

Step 1: ovarian stimulation

For roughly two weeks you take hormone injections to encourage the ovaries to mature several eggs, with scans and blood tests to monitor progress.

Step 2: egg collection

When the eggs are ready, a doctor collects them using a fine needle guided through the vaginal wall — a minor procedure that takes around 20 minutes. This is done under sedation or light general anaesthesia, so you are comfortable and usually go home the same day.

Step 3: fertilisation

In the lab, eggs are fertilised with sperm. For PGT, clinics often use ICSI (intracytoplasmic sperm injection), where a single sperm is injected into each egg, to avoid stray sperm DNA confusing the genetic test.

Step 4: growing to the blastocyst stage

The fertilised eggs are grown for about five to six days until they reach the blastocyst stage — a ball of roughly 100 or more cells.

Step 5: the biopsy

This is the test itself. Using a laser and fine instruments, an embryologist removes about five to ten cells from the trophectoderm — the outer layer that would go on to form the placenta, not the part that becomes the baby. Because so few cells are taken from a much larger embryo, this is not expected to harm its development. Each biopsy takes only minutes.

Step 6: freezing and testing

After biopsy the embryos are vitrified (fast-frozen) while the cell samples go to the genetics lab. Results usually take about one to three weeks.

Step 7: frozen embryo transfer

Once results are back, a suitable embryo is thawed and placed in the womb through a thin tube — a quick, painless outpatient step that needs no anaesthesia.

The genetic test happens entirely in the laboratory, so there is nothing for you to recover from after the biopsy itself. Recovery relates to the IVF steps around it.

• After egg collection: because you have had sedation or light anaesthesia, you should not drive that day and will usually rest. Mild cramping, bloating or light spotting for a day or two is common. Most people are back to normal activity within a day or two.
• While you wait for results: there is no physical recovery, but the wait of one to three weeks can feel long. This is a normal, expected pause.
• After the frozen embryo transfer: this is gentle and outpatient. Many clinics let you go about a normal day afterwards; some suggest taking it easy. You will typically take hormone support (such as progesterone) as directed.
• The pregnancy test: usually about 10-14 days after the transfer, with an early ultrasound scan a few weeks later if it is positive.

A rare disappointment to be prepared for: occasionally all the embryos test abnormal, which means there is nothing suitable to transfer in that cycle. Your clinic should explain what this means and what the options are.

Embryo testing is widely used and generally considered safe, but it is not risk-free or perfect. Honest counselling should cover the following.

• The result can be wrong. No genetic test is 100% accurate. There can be false positives (a healthy embryo labelled abnormal, which might then be discarded) and false negatives (an affected embryo passing as normal). Problems such as allele dropout (one copy of a gene not showing up), DNA contamination, or an inconclusive sample can occur.
• The biopsy carries a small risk to the embryo. Removing cells is delicate; while most embryos tolerate it well, there is a small chance an embryo could be damaged.
• Mosaic and inconclusive results can be hard to interpret and may lead to a difficult decision or a repeat biopsy.
• Fewer embryos to use. As a selection tool, PGT can reduce the number of embryos available for transfer.
• It does not test for everything. PGT-A counts chromosomes; PGT-M checks one named gene. Neither rules out every possible genetic or developmental condition, and neither guarantees a healthy baby.
• IVF-related risks still apply, such as a reaction to the stimulation medicines (ovarian hyperstimulation) and the small risks of egg collection.

Because of the small chance of an inaccurate result, professional bodies recommend that anyone who conceives after PGT-M is offered confirmatory prenatal testing during pregnancy — such as chorionic villus sampling or amniocentesis — to check the result.

"Results" here means two different things, so it helps to separate them.

The lab report tells you which embryos are euploid, aneuploid or mosaic (for PGT-A), or which are unaffected by the family condition (for PGT-M and PGT-SR). This report does not expire — a frozen, tested embryo keeps its result, and embryos can be stored frozen for years and transferred later.

The clinical outcome is the real-world question: does testing improve your chance of a healthy baby? The honest answer depends on your situation. Choosing a euploid embryo can shorten the path to pregnancy for some people and may lower the miscarriage rate, especially in older women, but the HFEA notes that for most IVF patients there is no proven increase in the overall live-birth rate. Importantly, testing reduces the chance of miscarriage but does not remove it, because miscarriage has other causes too. A normal PGT result is reassuring, but it is not a guarantee of a healthy pregnancy or baby.

For PGT-M and PGT-SR, the value is clearer: for families carrying a serious inherited condition, the test can substantially lower the chance of passing that specific condition on — which is why confirmatory testing in pregnancy is still advised.

Embryo testing is priced on top of the IVF cycle, and there are usually two parts: a fee for the embryologist to take the biopsy, and a fee for the genetics laboratory to analyse the samples. Some clinics charge a flat fee for a batch of embryos; others charge per embryo, so a cycle with more embryos costs more.

As an indicative range only, the genetic testing component (PGT-A) commonly falls somewhere around EUR 1,500 to EUR 5,000 in Europe and Turkiye, on top of the IVF cycle itself. PGT-M (PGD) is often more expensive than PGT-A because a bespoke test usually has to be designed for your family first, sometimes with a separate set-up fee before the cycle even begins.

What changes the price:

• How many embryos are biopsied and tested.
• Which test you need (PGT-A is generally cheaper than a custom PGT-M).
• Whether a one-off test "set-up" or probe-design fee applies (common for PGT-M).
• Whether the quote includes the freezing and later frozen embryo transfer, which testing makes necessary.
• The clinic, the laboratory used, and what is bundled into a package.

These figures are a rough guide to help you budget — they vary by case, by clinic and by laboratory, and are not a quote. Always ask for a written, itemised price that states clearly what is and is not included.

Turkiye has become a well-known destination for IVF, drawing patients from across Europe, the Gulf and the former Soviet states. The usual reasons are a combination of experienced fertility units, modern laboratories, shorter waiting times and prices that can be lower than in many Western European countries — without, for accredited clinics, a drop in standards.

There are some local rules you must know before planning treatment in Turkiye:

• IVF is restricted to married couples using their own eggs and sperm. Egg, sperm and embryo donation, and surrogacy, are not permitted under Turkish law.
• PGT-M/PGD and PGT-A are allowed for medical reasons, such as screening for genetic conditions.
• Sex selection for non-medical (social) reasons is prohibited.

To choose a clinic safely, verify the following:

• Hospital accreditation. Look for international accreditation such as JCI (Joint Commission International), and ask whether the embryology and genetics laboratory holds its own quality accreditation (for example ISO 15189 for medical laboratories).
• The specialists' credentials. Confirm that the reproductive specialist is board-certified and that a qualified clinical geneticist or genetic counsellor is involved — essential for PGT-M.
• Which genetics lab does the testing and what method it uses.
• Clear, written pricing and honest discussion of success rates for someone in your age group and situation — be wary of anyone quoting guaranteed results.
• How records, consent and aftercare are handled, and who your point of contact is once you are home.

Good preparation makes embryo testing smoother and the results easier to act on.

Before you travel or commit:

• Gather your medical history, any previous IVF or miscarriage records, and — for PGT-M — details and, ideally, genetic test results of the condition in your family. PGT-M usually needs parental (and sometimes relatives') DNA to design the test in advance, so start this early.
• Ask for a genetic counselling session if any single-gene or chromosome condition is involved.
• Plan the timeline: a stimulation phase of about two weeks, then results that take one to three weeks, then a separate frozen transfer visit.

Questions worth asking your clinic:

• Which test do I actually need — PGT-A, PGT-M or PGT-SR — and why?
• Based on my age and history, is testing likely to help me, and what does the evidence say for someone like me?
• How many embryos do you expect, and what happens if none test suitable?
• How do you handle mosaic or inconclusive results?
• What is the test's accuracy, and do you recommend confirmatory testing in pregnancy?
• Is the price per embryo or per batch, and exactly what is included?
• Who performs the biopsy and which laboratory analyses it?
• How will follow-up and the frozen transfer be arranged around my travel?

Because testing requires the embryos to be frozen while the lab works, treatment with PGT is almost always split into stages, which suits international patients well.

A common pattern is: one trip for stimulation and egg collection, then you return home while the embryos are tested and stored, and a second, shorter trip later for the frozen embryo transfer. Some people prefer to stay nearby for the whole sequence; discuss what fits your life and budget.

When is it safe to fly? The genetic test does not involve any procedure on your body, so it places no restriction on flying. Around egg collection, you have had sedation or light anaesthesia and a minor procedure, so it is sensible not to travel on the same day; many clinics suggest waiting a day or two and feeling well before a longer journey. The embryo transfer is gentle and does not, by itself, prevent flying — but follow your own clinic's advice, since they know your case. If you develop significant pain, heavy bleeding, fever or marked bloating (a possible sign of ovarian hyperstimulation), seek medical care before travelling.

Practical aftercare tips:

• Keep copies of your lab reports, consent forms and medication plan.
• Take your prescribed hormone support exactly as instructed after a transfer.
• Agree in advance how the clinic will share results and stay reachable once you are home.
• Arrange any recommended early pregnancy scan, and remember that confirmatory prenatal testing may be offered if you used PGT-M.