Which test is possible after a miscarriage depends mostly on timing: whether the pregnancy is still in your womb, whether tissue was saved, and what happened in any earlier pregnancies. We walk through those questions below so you can see which routes are open to you now.
Testing is always optional. If there is heavy bleeding or severe pain, or you feel unwell, get medical care first. Your safety comes before any test, and our genetic counsellors can go through the options with you afterwards.
Before you start
In roughly half of early miscarriages, the cause is a chromosome change in the pregnancy: too many or too few chromosomes, or pieces in the wrong arrangement. Chromosomes are the packages that carry genetic information. Such changes typically happen at random when an egg or sperm is produced, or during the earliest cell divisions, and nothing you did caused them.
A test can sometimes show whether that is what happened. That may ease the search for a reason, show whether further investigations would help, and inform planning for a future pregnancy. No test can guarantee an explanation, though, and a result showing no chromosome change leaves other causes open.
Which test is possible comes down to a practical question: where can a sample come from? It might be your blood before the pregnancy has passed, the pregnancy tissue afterwards, or, in some situations, blood from both partners. Deciding not to test is just as valid a choice, and we will support you whichever way you go.
Step by step
Testing only makes sense once the diagnosis is certain. NICE guidance asks for a second specialist's view, a repeat scan at least 7 days later, or both, before a miscarriage is confirmed. If the pregnancy measured below set sizes, the repeat scan is always needed, and it is at least 14 days later if only an abdominal scan was possible.
If it has not, you are in situation A below: a blood-based test may be possible now, before tablets or surgery, and tissue may still be kept for testing afterwards. If it has already passed or been removed, go on to the next question.
If tissue was collected at home, in hospital or during surgery and not put in preservative, situation B applies. If nothing was kept, or the sample could not be tested, situation C applies.
If you have had recurrent miscarriages (three or more in UK guidance, two or more in European guidance), or a tissue result showed an unbalanced rearrangement, situation D applies as well. It can sit alongside A, B or C.
The four routes
Many people fit more than one situation. Someone whose third miscarriage has not yet passed, for example, may be weighing up A and D together.
This applies after a missed miscarriage or an empty sac that has not yet come away. While tissue remains, the placenta keeps releasing small pieces of its DNA into your bloodstream, which a laboratory can examine for extra or missing chromosomes.
A scan shortly before the sample confirms the tissue is still there. Once it passes or is removed, the placental DNA in your blood starts to fall; in a large Danish study it dropped noticeably after about 12 hours, and more samples gave no result. Read more about the blood test and testing before the miscarriage completes.
If you choose surgery, or may pass tissue at home, ask your early pregnancy unit whether that tissue can be kept fresh for testing too. If you are weighing up a blood-based test, one of our genetic counsellors can go through what it can and cannot show before any tablets or surgery.
Tissue passed at home or removed during surgery is often testable when it has been kept fresh in a sterile pot (dry, or in a small amount of sterile saline) rather than in formalin, the fixative used for routine pathology. NHS laboratories typically run a rapid test for common chromosome changes and a chromosomal microarray, which checks every chromosome for extra or missing material, including pieces too small to see under a microscope.
UK guidance is to offer tissue testing from the third miscarriage onwards and after any second-trimester loss; NHS criteria also allow it after a single miscarriage with features suggesting a chromosome condition. Outside these situations it is not usually offered on the NHS, but it can be arranged privately, starting with a conversation with one of our genetic counsellors.
If the sample turns out to be your own tissue, a SNP-based microarray or your blood tested alongside can show this. See pregnancy tissue testing.
This is common and nobody's fault. Researchers in Copenhagen found that roughly a third of women ended up without a testable sample, either because nothing could be collected or because what was collected was probably their own tissue. If the pregnancy passed within about the last day, a blood sample may still work, though less often: in Danish research, about 9 in 100 samples gave no result while tissue was still in the womb, against about 27 in 100 taken 12 to 24 hours after it had passed.
It is worth asking whether a laboratory accepts samples taken after the pregnancy has passed. Otherwise, this pregnancy usually cannot be tested, and what makes sense next depends on your history.
A balanced rearrangement means a parent has the full amount of chromosome material, but with some segments swapped or flipped. The carrier is well, yet an embryo may receive an unbalanced copy, with material missing or extra. Among couples with recurrent miscarriage, roughly 3 to 6 in every 100 include a carrier.
UK guidance (RCOG) recommends offering both partners a chromosome test, a parental karyotype, when pregnancy tissue shows an unbalanced rearrangement or could not be tested (NHS criteria for the latter are narrower). European guidance advises it only after an individual risk assessment.
Carriers still have a good outlook. In a large Dutch study that followed couples for about six years, a healthy child was born to 83 in 100 carrier couples, compared with 84 in 100 couples without a rearrangement. Carriers were more likely to have another miscarriage along the way, though: about 49 in 100, against 30 in 100.
A genetics specialist can explain the options, including testing during pregnancy, or IVF with embryo testing (PGT-SR), which may reduce miscarriages but has not been shown to improve the overall chance of having a baby.
Recurrent miscarriage also calls for checks beyond genetics, such as blood tests for antiphospholipid syndrome, thyroid tests and an ultrasound assessment of the womb's shape. See recurrent miscarriage.
In numbers
These figures describe groups of people in published studies and guidelines, not what will happen in any one situation.
At a glance
No single test answers every question. This summary sets the main options side by side, and most of them have their own page with more detail.
| Test | Sample | Can show | Cannot show |
|---|---|---|---|
| Blood-based test (cell-free DNA) | Your blood, taken before the pregnancy has passed | Extra or missing chromosomes, in roughly 4 of every 5 cases that tissue testing would find (about 78 in 100) | Triploidy with most methods, balanced rearrangements, small changes or single-gene conditions. The result is screening-type, not a diagnosis: sometimes there is no result, and occasionally it reflects a change confined to the placenta, or your own DNA |
| Rapid tissue test (often QF-PCR) | Pregnancy tissue | Extra or missing copies of a few selected chromosomes | Most other chromosomes and smaller pieces, which is why a microarray usually follows |
| Chromosomal microarray on tissue | Pregnancy tissue kept fresh, without preservative | Whole extra or missing chromosomes, plus smaller gains and losses anywhere in the genome; SNP-based arrays (not all arrays) can also pick up triploidy and contamination by your own cells | Balanced rearrangements or most single-gene changes. Occasionally finds a change of uncertain meaning |
| Karyotype on tissue (older method) | Pregnancy tissue containing living cells | Whole-chromosome changes and larger structural changes visible under a microscope | Anything at all if the cells fail to grow, which happens in about 1 in 5 samples. Your own cells can overgrow and give a misleading 'normal female' result |
| Parental karyotype | Blood from each partner | Whether either partner carries a balanced rearrangement that could affect future pregnancies | What caused a particular miscarriage. Most chromosome changes in a pregnancy arise by chance in parents whose own chromosomes are normal |
A blood result and a tissue result can be used together: testing the tissue can confirm a blood result or pick up changes it misses, such as triploidy.
Methods differ between laboratories, so it is worth asking what a specific test has been checked for and what it cannot detect.
Results and next steps
A result is easier to make sense of with someone who has genetics training, such as one of our genetic counsellors or, for more complex findings, a consultant in clinical genetics. In broad terms, results fall into a few groups, and each points to a different next step.
When you feel ready to look ahead, preparing for your next pregnancy and planning a pregnancy after a chromosomal loss cover what can be planned, and chromosomal causes explains the main types of change.
Getting advice
If you are under the care of an NHS early pregnancy unit, ask that team first whether tissue can be kept and tested, and how it should be stored. After recurrent miscarriage, a specialist recurrent miscarriage clinic can coordinate wider investigations, including genetic tests where they are indicated. The blood-based test is not yet part of standard NHS care and is still being studied in UK research, so outside a study it is generally only available privately.
Our genetic counsellors can help you work out which test, if any, suits your circumstances, and what each possible result would mean for you, before you commit to anything. Appointments are by video, so your partner can join from wherever they are.
If the diagnosis itself still feels uncertain, an early scan at 6 to 9 weeks or a second-opinion scan from around 10 weeks can come first.
Whatever you decide, you do not have to manage it alone. The Miscarriage UK support line is 0303 003 6464, and the free Tommy's midwife line is 0800 0147 800 (Monday to Friday, 9am to 5pm).
How we can help
Your NHS care carries on whatever you choose. If you would like help deciding, or your situation points towards parental testing or wider investigations, these are the appointments we offer. You can book them yourself, without a referral, or call us if you are not sure which fits. London Miscarriage Clinic is part of London Pregnancy Clinic, so booking opens on the London Pregnancy Clinic website.
Online, 30 minutes
A video appointment with one of our registered genetic counsellors, a team led by Ms Ailidh Watson. Work out which of the four situations applies to you, whether a blood or tissue test is possible now, and how tissue would need to be kept, before committing to anything. Partners are welcome to join. A 60-minute appointment gives more time for a complex history.
Only when indicated
A blood test that checks one or both partners for a balanced rearrangement. It is not needed after most miscarriages; it is most useful when tissue showed an unbalanced rearrangement, or after recurrent losses where tissue could not be tested. Testing a couple is £550, and results usually take two to three weeks.
After repeated losses
A consultation and pelvic scan with a consultant gynaecologist at our City clinic in Spitalfields, with blood tests that include lupus anticoagulant and anticardiolipin antibodies (checks for antiphospholipid syndrome) and a thyroid profile. Booking takes a £300 deposit, which comes off the package price. A parental karyotype is separate.
Doctor-led, by enquiry
For a result that is unusual, uncertain or repeated, or a family history of a chromosome condition, Dr Harry Leitch, Consultant in Clinical Genetics, can review your reports and advise whether further testing would help. Appointments are arranged by enquiry.
Usually not. After a single miscarriage, any chromosome change in the pregnancy most likely arose by chance, and in most cases both parents have normal chromosomes themselves. UK guidance keeps parental testing for particular situations, mainly when pregnancy tissue shows an unbalanced rearrangement, or after recurrent losses where tissue could not be tested. European guidance suggests it only after an individual risk assessment, for example if a chromosome rearrangement runs in the family.
Testing the pregnancy tissue is the usual reference point, and blood-test studies measure themselves against it. Pooled across eight studies, and leaving aside triploidy, which these blood tests cannot detect, blood tests picked up roughly 78 of every 100 chromosome changes that tissue testing identified, and correctly reported about 91 in 100 pregnancies whose tissue showed no change.
So a blood result showing no change makes a chromosome cause less likely but cannot rule it out. Tissue testing has its own weak spots: samples can fail, or turn out to be your own cells.
It can. In the UK, tissue testing is usually offered after any miscarriage in the second trimester, not only from the third early loss. Most research on the blood test has involved first-trimester losses. After a miscarriage, the share of placental DNA in the blood is often low, which is one reason a blood sample sometimes gives no result.
It happens with every method, and it does not mean anything was done wrong. In a Danish study of 1,000 women, about 11 in 100 blood samples were inconclusive. Tissue can fail too, especially with the older culture-based karyotype, where the cells do not grow in about 1 in 5 cases. After recurrent losses with no successful result, testing both partners may be offered, although NHS guidance notes this tells you less than a result from a pregnancy.
It works on the same principle, reading placental DNA in the mother's blood, but in a different situation. After a miscarriage there is often much less placental DNA, and laboratories may need settings adapted for pregnancy loss. In one study, detection rose from about 55 in 100 with standard NIPT settings to about 82 in 100 with adjusted ones, at the cost of a few more false alarms. It is reasonable to ask whether a test has been checked specifically in pregnancy loss.
No. You can book a genetic counselling appointment, a parental karyotype or the recurrent miscarriage package yourself, without a GP referral, and your NHS early pregnancy unit or GP can stay involved. Testing of pregnancy tissue is not booked online: it starts with a genetic counselling appointment, where the counsellor explains whether testing is possible and how a sample would need to be collected. If you can, have copies of earlier scan reports and results to hand.
This page is general information to help you find your way around the options. It is not personal medical advice and cannot decide on its own which test is right for you; that is a conversation to have with the professionals caring for you, including our team if you see us. Should you develop heavy bleeding, severe pain, a fever or faintness, do not wait: phone your early pregnancy unit, call NHS 111, or dial 999 in an emergency.
Contact
The figures and clinical statements on this page are drawn from the sources below. Guidance evolves — always discuss your individual circumstances with a clinician.
