Clarity miscarriage test | Advanced fertility testing | Care Fertility

Clarity miscarriage test

Genetic testing after pregnancy loss, to help you understand what happened.

We are so sorry you’re going through this. A pregnancy loss can feel sudden, confusing, and deeply painful. It’s normal to want answers, and it’s also normal not to feel ready to think about testing straight away.

Clarity is an optional blood test that can sometimes help explain why a miscarriage happened. It looks for chromosomal differences that may have affected the pregnancy, helping you and your Care Fertility team understand whether the loss was likely linked to a chromosome change, or whether other causes may need to be considered.

Hear from our fertility specialist

In this video, Dr Tom Bamford, Medical Director of Care Fertility Manchester, Fertility Specialist and Clinical Lead for Research and Innovation, talks through Clarity and how it can support people after miscarriage.

He explains what the test looks for, why miscarriage can happen for reasons outside anyone’s control, and how Clarity may help identify whether a genetic cause was involved. He also talks about how your results may help your Care Fertility team understand what happened and guide conversations about future treatment, further investigations, or next steps that feel right for you.

What is the Clarity test?

Clarity is a genetic screening test used after miscarriage. It is provided by SABSCAN® at GNT Labs and arranged through Care Fertility.

The test uses a blood sample from your arm to analyse cell-free DNA in your bloodstream, including small fragments of DNA from the pregnancy. The laboratory looks across the chromosomes to check for missing or extra chromosomes, or larger missing or duplicated chromosome sections.

Chromosomes carry our genetic information. A typical pregnancy has 46 chromosomes, 23 from the egg and 23 from the sperm. Sometimes, by chance, an egg or sperm has too many or too few chromosomes. If this happens, the embryo may also have the wrong number of chromosomes, which is known as a chromosomal abnormality or aneuploidy.

Chromosomal abnormalities are one of the most common reasons for miscarriage, especially in early pregnancy. This is not caused by anything you did or did not do.

Why you might choose Clarity

Clarity may help you understand whether your miscarriage was likely caused by a chromosomal difference.

For some people, having a medical explanation can help reduce feelings of guilt or self-blame. For others, it can help guide conversations about future fertility treatment, further investigations, or options such as pre-implantation genetic testing for aneuploidy (PGT-A) in a future IVF cycle.

If the result suggests the pregnancy was likely chromosomally normal, your doctor may talk to you about whether further investigations could be helpful before moving forward with treatment.

Clarity is a simple blood test designed to help patients better understand the possible cause of a miscarriage. By analysing pregnancy DNA in the mother’s blood, the test can identify whether chromosomal abnormalities — the most common cause of early miscarriage — were likely involved. The results may provide reassurance, help reduce uncertainty, and support personalised planning for future fertility treatment.

Why miscarriage is often linked to chromosomes and age

Eggs are present from birth, so they age as we do. Over time, the way chromosomes divide inside the egg can become less precise. This means an embryo is more likely to develop with missing or extra chromosomes, which can make implantation less likely or lead to an early miscarriage.

This is one of the reasons miscarriage becomes more common with age. It does not mean anything has been done wrong, it is usually linked to changes that happen naturally over time.

Younger eggs

Eggs are more likely to have the expected number of chromosomes, giving an embryo a stronger chance of developing as expected.

With age

Chromosome division errors become more common, increasing the chance of an embryo developing with missing or extra chromosomes.

Later years

Embryos are more likely to have chromosome differences, which can make pregnancy harder to achieve and increase miscarriage risk.

Illustration of a euploid embryo

Euploid

A euploid embryo has the expected number of chromosomes, making it more likely to develop as expected during the early stages of pregnancy.

Illustration of a mosaic embryo

Mosaic

A mosaic embryo has both typical and atypical chromosome patterns, meaning development may continue, but the outcome can be harder to predict overall.

Illustration of an aneuploid embryo

Aneuploid

A mosaic embryo has both typical and atypical chromosome patterns, meaning development may continue, but the outcome can be harder to predict overall.

When does Clarity need to be done?

Timing is important. The sooner the blood sample is taken after miscarriage is diagnosed, the higher the chance of getting a clear result.

If you conceived through IVF, the sample should be taken from:

20 days after a day five blastocyst transfer, or
18 days after a day three transfer.

The test is most accurate from:

30 days after a day five transfer, or
28 days after a day three transfer.

If you conceived through intrauterine insemination (IUI) or timed intercourse, the test can be taken from five weeks of pregnancy onwards, calculated from the first day of your last menstrual period. Ideally, it is performed from seven weeks onwards, when the chance of getting a clear result is highest.

The sample should be taken as close as possible to the time the miscarriage is diagnosed, before any planned surgical management, and within 24 hours of heavy bleeding starting.

Low risk result

This means a chromosomal abnormality is unlikely, within the limits of the test.

It suggests the pregnancy was most likely chromosomally normal. Your clinician may recommend further assessment to look at other possible causes of miscarriage.

High risk result

This means there is a high likelihood that a chromosomal abnormality was present.

It strongly suggests the miscarriage was related to a chromosomal cause. Your clinician will explain what this may mean for future pregnancies and whether options such as PGT-A could be considered.

Repeat examination

Sometimes, it is not possible to get a clear result from the first analysis.

In this situation, the laboratory may check whether the same sample can be re-analysed. This may delay the final result slightly, but we’ll keep you informed.

No result

In around one to two out of every 100 tests, no result is possible.

This is usually because there is not enough pregnancy DNA in the blood sample. If this happens, a partial refund will be provided.

How accurate is Clarity?

Clarity is a highly reliable screening test, but no test is perfect.

For common chromosomal conditions, such as Down syndrome, the test is accurate in well over 99 out of 100 cases. For other larger chromosome changes it can detect, accuracy is around 95 out of 100.

Clarity is a screening test, not a diagnostic test. This means your result will always be interpreted alongside your wider clinical picture, so your Care Fertility team can give advice that is right for you.

What Clarity cannot detect

Clarity cannot detect every possible genetic or chromosomal condition.

It cannot detect:

triploidy or other polyploidies, where the pregnancy has an entire extra set of chromosomes
very small chromosomal changes
balanced chromosomal rearrangements
uniparental disomy, where both copies of a chromosome come from one parent
single-gene or inherited genetic conditions.

Your clinical team will explain your result clearly and talk to you about whether any further testing may be appropriate.

Who is Clarity not suitable for?

Clarity is not suitable for everyone.

It may not be appropriate if:

the pregnancy was created using a PGT-A confirmed chromosomally normal embryo
the pregnancy was less than five weeks gestation
fewer than 20 days have passed since embryo transfer
more than 24 hours have passed since the miscarriage completed
the pregnancy involved triplets
you or your partner have a known balanced chromosomal translocation
you or your partner have clinically significant sex chromosome mosaicism.

The test can be used in twin pregnancies, although accuracy may be slightly reduced.

Frequently Asked Questions

Is Clarity the same as testing pregnancy tissue? No. Clarity uses a blood sample from your arm. The laboratory analyses cell-free DNA in your blood, including small fragments of pregnancy DNA. This means it does not require a tissue sample from the pregnancy.

Can Clarity tell me why I miscarried? Clarity can sometimes help explain whether a miscarriage was likely linked to a chromosomal difference. It cannot identify every possible cause of miscarriage, and it is not a diagnostic test. Your result will be reviewed alongside your medical history and scan findings.

Will Clarity tell me the sex of the pregnancy? No, the sex of the pregnancy is not reported, unless a sex chromosome abnormality is identified.

Can I have Clarity after IVF? Yes, Clarity may be suitable after IVF, depending on the timing and your circumstances. If you conceived through IVF, the test can usually be taken from 20 days after a day five transfer, or 18 days after a day three transfer.

What happens if my result is high risk? A high risk result means there is a high likelihood that a chromosomal abnormality was present. Your clinician will explain what this means and whether any future treatment options, such as PGT-A, may be worth discussing.

What happens if my result is low risk? A low risk result means a chromosomal abnormality is unlikely, within the limits of the test. Your clinician may discuss whether further investigations could help look for other possible causes of miscarriage.