Recurrent Miscarriage: Causes, Tests, Treatment and Planning Your Next Pregnancy

Recurrent miscarriage is the loss of two or more pregnancies, usually early in pregnancy. For some couples, repeated loss is linked to a cause that can be found and treated. For many others, tests come back normal, and that brings its own kind of frustration.

Below, we look at what doctors mean by recurrent miscarriage, the causes that are known, the tests that actually help (and a few that don't), treatment that has evidence behind it, and what to do before and during your next pregnancy.

One thing first. A miscarriage is very rarely caused by something the mother did or didn't do. And most women who have had recurrent miscarriages do go on to have a baby.

What does recurrent miscarriage mean?

A miscarriage is the loss of a pregnancy before the baby could survive outside the womb. When this happens more than once, doctors call it recurrent miscarriage or recurrent pregnancy loss (RPL).

The exact definition depends on which guideline you read. The European Society of Human Reproduction and Embryology (ESHRE) and the American Society for Reproductive Medicine (ASRM) use two or more pregnancy losses. The Royal College of Obstetricians and Gynaecologists (RCOG) in the UK uses three or more first trimester miscarriages, or any loss in the second trimester. Even so, the RCOG leaves room for doctors to start investigations after two losses if that seems sensible.

The losses don't have to be one after another, and they don't have to be with the same partner. Ectopic and molar pregnancies are counted separately.

How common is it?

Having one miscarriage is common. Having several is not. Recurrent pregnancy loss is thought to affect roughly 1 to 2 in every 100 couples trying for a baby.

I've had one miscarriage. Will it happen again?

Probably not. Most women who miscarry once have a healthy pregnancy the next time. A single loss is usually down to a chance chromosomal error in that particular embryo, and lightning rarely strikes the same way twice.

Why does recurrent miscarriage happen?

There isn't one answer. Some couples have a clear cause, some have more than one contributing factor, and a large group have none that current tests can find. Doctors call the last situation unexplained recurrent miscarriage.

Chromosomal errors in the pregnancy

Chromosomes are the packages that carry our genes. If an embryo ends up with an extra or missing chromosome, it usually can't develop properly and the pregnancy stops growing.

This is the single most common reason for miscarriage. These errors happen by chance as the egg or sperm is formed, and they become more likely as a woman gets older. That's a large part of why miscarriage risk climbs after the mid-thirties.

A balanced translocation in one parent

Occasionally, one partner carries what's called a balanced translocation. Two chromosomes have swapped segments, but nothing is lost, so the person is healthy and usually has no idea. The trouble comes when some eggs or sperm carry an uneven share of that material. A pregnancy that inherits the unbalanced version may miscarry.

Antiphospholipid syndrome (APS)

APS is an autoimmune condition. The body produces antibodies that make the blood more prone to clotting, and this can interfere with how the placenta develops.

It's worth singling out because it can be treated. APS is also linked with problems later in pregnancy, including pre-eclampsia and poor growth of the baby, so women who have it need watching closely right through to delivery.

The shape of the uterus

Some women are born with a uterus that is shaped a little differently. The difference most clearly tied to recurrent miscarriage is a uterine septum, a wall of tissue that partly or fully divides the inside of the womb.

Fibroids that bulge into the cavity, polyps and scar tissue may matter for some women too. How much they matter is less certain, and doctors weigh this case by case.

Cervical weakness and later losses

A loss in the second trimester sometimes happens because the cervix, the neck of the womb, shortens and opens too early, often without much pain. This is known as cervical insufficiency. It behaves differently from early miscarriage and is managed differently too.

Hormones and general health

Poorly controlled diabetes around the time of conception raises the risk of miscarriage. So does thyroid disease when hormone levels are clearly abnormal. Polycystic ovary syndrome (PCOS) has also been linked, although researchers are still working out how strong that link really is.

Age and lifestyle

A woman's age is one of the strongest risk factors we know of. A father's age seems to play a smaller part, mostly after 40.

Smoking, heavy drinking and being well above a healthy weight can also add to the risk. They're rarely the whole story, but they're things you can change, which makes them worth tackling.

Things that don't cause miscarriage

Going to work doesn't. Neither does climbing stairs, travelling, having sex, gentle exercise or eating normal home food. And despite what relatives may say, there's no good evidence that stress causes a pregnancy to be lost. The strain of losing pregnancies is real, of course, and it deserves proper support.

Which tests are useful after recurrent miscarriage?

The purpose of testing is simple. Find anything that can be treated, or anything that changes how the next pregnancy should be planned. Your doctor will tailor the tests to your history, how many losses you've had, when in pregnancy they happened, and your general health.

Antiphospholipid antibody tests

These blood tests look for lupus anticoagulant and anticardiolipin antibodies, and sometimes anti-beta-2 glycoprotein I antibodies. It's best to do them before trying again.

A positive result is normally rechecked about 12 weeks later. Antibodies can appear briefly after an infection, so a second positive test is what confirms APS.

An ultrasound of the uterus

A pelvic scan, often a 3D ultrasound, shows the shape of the womb and can pick up a septum, fibroids or other structural differences. If something shows up, your doctor may suggest further imaging or a hysteroscopy, where a slim camera is passed through the cervix to look inside.

Testing the pregnancy tissue

After a miscarriage, the tissue can be sent for chromosome analysis. Guidelines suggest offering this especially from the third loss onwards.

The result can be surprisingly helpful. If it shows a random chromosomal error, that explains the loss and is often reassuring for the future. If it shows an unbalanced chromosome arrangement, testing both parents is usually the next step.

Parental karyotype

This is a blood test that checks whether either partner carries a balanced translocation. It tends to be advised when the tissue result points that way, or when tissue couldn't be tested. Results should always come with genetic counselling, because the implications aren't obvious from the report alone.

Thyroid and sugar levels

Thyroid function is usually checked, and thyroid antibodies (TPO antibodies) may be too. If diabetes is suspected, a blood sugar test such as HbA1c might be added. Beyond that, hormone tests depend on the individual.

Tests you probably don't need

Some tests are offered widely but aren't backed by good evidence for routine use in recurrent miscarriage. These include screening for inherited clotting conditions such as protein C deficiency, antithrombin deficiency and MTHFR variants, natural killer (NK) cell tests, HLA matching between partners, and routine androgen tests.

There are exceptions. After a second trimester loss, or if you or a close relative has had blood clots, selected clotting tests may be reasonable. It's better to ask your specialist which tests suit your history than to request a large panel.

What treatments are available?

That depends on what the tests find. When there's a cause, treatment targets it. When there isn't, good care means support and monitoring, and avoiding treatments that haven't been shown to work.

Aspirin and heparin for APS

Women with APS and recurrent miscarriage are usually given low-dose aspirin together with heparin injections during pregnancy. Heparin thins the blood and doesn't cross the placenta. Used together, they can improve the chances of a successful pregnancy.

APS still carries a higher risk of complications later on. Expect extra growth scans, often with Doppler checks of blood flow to the baby.

Surgery for a septum

If a septum is found, it can be removed during a hysteroscopy. Whether that's advisable depends on its size and your history, and it's a decision to make carefully with your gynaecologist.

With fibroids and other cavity problems, it's less clear that surgery lowers miscarriage risk. Again, the answer is individual.

Progesterone if you bleed in early pregnancy

Progesterone is a hormone that helps support a young pregnancy. UK guidance suggests progesterone should be considered for women who have miscarried before and then have bleeding in early pregnancy.

Without bleeding, the picture changes. For unexplained recurrent miscarriage with no bleeding, there isn't enough evidence that progesterone helps. Your doctor can tell you whether it makes sense in your case, and how to use it.

Thyroid disease and diabetes

An underactive thyroid with clearly abnormal hormone levels is normally treated with thyroid hormone before and through pregnancy. If you have diabetes, getting blood sugar well controlled before conceiving is one of the most useful things you can do.

What about women whose thyroid levels are normal but who test positive for thyroid antibodies? Routine thyroid hormone treatment isn't recommended for them, as trials haven't shown a benefit.

If one partner carries a balanced translocation

Couples in this situation are usually referred for genetic counselling. The counsellor will go through the chance of further loss and what the options are. Some couples simply try again naturally with early monitoring, and many succeed. Others consider IVF with preimplantation genetic testing (PGT), where embryos are checked before transfer. Prenatal diagnostic testing such as CVS or amniocentesis is another option in a future pregnancy, and some couples explore other ways of building their family.

None of these is the "right" choice for everyone. The decision belongs to the couple.

Second trimester loss

If an earlier loss looks like it was caused by cervical weakness, the next pregnancy may involve scans to measure the length of the cervix. Some women are offered a cervical stitch (cerclage). A specialist will decide this with you.

When no cause is found

Being told that everything is normal can feel like no answer at all. But in this group the outlook is often good, and many women carry the next pregnancy to term without any specific medicine.

UK guidance advises against aspirin or heparin for unexplained recurrent miscarriage. Steroids, intravenous immunoglobulin (IVIG) and other immune treatments aren't recommended outside research studies. They haven't been shown to help, and they cost money and carry risks of their own.

What does seem to help is organised, supportive care. That means being seen early by a team that knows your history, having early scans for reassurance, and knowing exactly who to call if something worries you.

How to prepare for your next pregnancy

Planning ahead gives your doctors time to finish tests and start treatment before you conceive. Many couples also find it helps them feel less at the mercy of chance.

Before trying again

Finish your investigations first, since some tests need repeating and the results can change the plan. Start folic acid before conception and ask your doctor what dose is right for you. If you have thyroid disease, diabetes, high blood pressure or another long-term condition, aim to have it well controlled. Go through your medicines with your doctor too, because some aren't suitable in pregnancy, but don't stop anything prescribed on your own.

Lifestyle changes are worth making where they apply. Stop smoking, avoid alcohol, keep caffeine modest and work gradually towards a healthy weight.

And look after your mind as well as your body. Grief after repeated loss can hit both partners, sometimes at different times and in different ways. Counselling or a support group can make a real difference.

How long should you wait?

There's no fixed waiting period that suits everyone. Physical recovery is only half of it. Feeling emotionally ready matters just as much. If tests or treatment are planned, your doctor may suggest finishing those first.

The first weeks of the next pregnancy

Get in touch with your doctor or clinic as soon as the test is positive. Depending on your situation, you may start planned medicines such as aspirin and heparin at this point. An early viability scan can confirm that the pregnancy is inside the womb and developing. You should also leave that first appointment knowing who to contact if you bleed or have pain.

An early scan can't stop a miscarriage from happening. Still, most couples find it hugely reassuring, and it means any problem is picked up quickly.

Will you need extra scans later?

It depends on the cause. With APS, closer monitoring usually continues throughout, including growth scans with Doppler. With unexplained recurrent miscarriage and a pregnancy that's going well, care often returns to a more routine pattern, guided by your obstetrician.

When to get urgent medical help

If you're pregnant, contact your obstetrician promptly or go for urgent assessment if you have:

• Heavy bleeding, especially soaking a pad within an hour
• Severe pain, or pain on one side of the lower abdomen
• Pain in the shoulder tip, dizziness or fainting, which can be signs of an ectopic pregnancy
• Fever, a foul-smelling discharge or feeling very unwell after a miscarriage
• Fluid leaking from the vagina in the second trimester

Light spotting in early pregnancy is common and doesn't always mean a miscarriage is happening. It's still worth mentioning to your doctor.

When to see a specialist

Ask about referral to a recurrent miscarriage clinic if you've had two or more miscarriages, particularly if you're over 35. The same applies after three first trimester losses or any loss in the second trimester. It's also sensible if you have a condition such as APS, lupus, diabetes or thyroid disease, or if an earlier pregnancy involved stillbirth, severe pre-eclampsia or a baby who didn't grow well.

A specialist clinic can arrange the right tests (and skip the unnecessary ones), explain results in plain terms, set up genetic counselling if it's needed and plan your care for next time.

Questions worth asking at your appointment

• Which tests do you recommend for me, and why?
• Should tissue from any future miscarriage be tested?
• Do my results suggest something treatable?
• Should I start anything before trying again?
• What will my care look like in early pregnancy?
• Who do I call if I have bleeding or pain?

After more than one loss, wanting an explanation is completely natural. A careful, evidence-based evaluation sometimes finds a treatable cause. When it doesn't, the odds for the next pregnancy are often better than couples expect.

A good starting point is a conversation with a specialist who can go through your history, suggest only the tests likely to help and plan the next pregnancy alongside you. Trichy Fetal Medicine and Fertility Centre runs a recurrent miscarriage clinic, and couples in and around Trichy can get in touch through the centre's website, https://fmctrichy.com/.

You can read about how we run the recurrent miscarriages clinic at our centre, and who performs it, on the team page.

Related guides

• How Many Miscarriages Count as Recurrent Pregnancy Loss?
• What Tests Are Done After Repeated Miscarriages?
• Can Genetic Problems Cause Recurrent Miscarriage?
• Before Trying to Conceive After a Miscarriage
• Pregnancy After Recurrent Miscarriage: How It Is Monitored