Overview

A miscarriage is the loss of a pregnancy during the first 23 weeks.

Symptoms of a miscarriage

The main sign of a miscarriage is vaginal bleeding, which may be followed by cramping and pain in your lower abdomen.

If you have vaginal bleeding, contact a GP or your midwife.

Most GPs can refer you to an early pregnancy unit at your local hospital straight away if necessary.

You may be referred to a maternity ward if your pregnancy is at a later stage.

But bear in mind that light vaginal bleeding is relatively common during the first trimester (first 3 months) of pregnancy and does not necessarily mean you're having a miscarriage.

What causes a miscarriage?

There are probably many reasons why a miscarriage may happen, although the cause is not usually identified.

The majority are not caused by anything the mother has done.

It's thought most miscarriages are caused by abnormal chromosomes in the baby.

Chromosomes are genetic "building blocks" that guide the development of a baby.

If a baby has too many or not enough chromosomes, it will not develop properly.

For most women, a miscarriage is a one-off event and they go on to have a successful pregnancy in the future.

Can miscarriages be prevented?

The majority of miscarriages cannot be prevented.

But there are some things you can do to reduce the risk of a miscarriage.

Avoid smoking, drinking alcohol and using drugs while pregnant.

Being a healthy weight before getting pregnant, eating a healthy diet and reducing your risk of infection can also help.

What happens if you think you're having a miscarriage?

If you have the symptoms of a miscarriage, you'll usually be referred to a hospital for tests.

In most cases, an ultrasound scan can determine if you're having a miscarriage.

When a miscarriage is confirmed, you'll need to talk to your doctor or midwife about the options for the management of the end of the pregnancy.

Often the pregnancy tissue will pass out naturally in 1 or 2 weeks.

Sometimes medicine to assist the passage of the tissue may be recommended, or you can choose to have minor surgery to remove it if you do not want to wait.

After a miscarriage

A miscarriage can be an emotionally and physically draining experience.

You may have feelings of guilt, shock and anger.

Advice and support is available at this time from hospital counselling services and charity groups.

You may also find it beneficial to have a memorial for your lost baby.

You can try for another baby as soon as your symptoms have settled and you're emotionally and physically ready.

Having a miscarriage does not necessarily mean you'll have another if you get pregnant again.

Most women are able to have a healthy pregnancy after a miscarriage, even in cases of recurrent miscarriages.

How common are miscarriages?

Miscarriages are much more common than most people realise.

Among women who know they're pregnant, it's estimated about 1 in 8 pregnancies will end in miscarriage.

Many more miscarriages happen before a woman is even aware she has become pregnant.

Losing 3 or more pregnancies in a row (recurrent miscarriages) is uncommon and only affects around 1 in 100 women.

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Symptoms

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Who can get it

There are many reasons why a miscarriage may happen, although the cause is often not identified.

If a miscarriage happens during the first trimester of pregnancy (the first 3 months), it's usually caused by problems with the unborn baby (foetus). About 3 in every 4 miscarriages happen during this period.

If a miscarriage happens after the first trimester of pregnancy, it may be the result of things like an underlying health condition in the mother.

These late miscarriages may also be caused by an infection around the baby, which leads to the bag of waters breaking before any pain or bleeding. Sometimes they can be caused by the neck of the womb opening too soon.

First trimester miscarriages

First trimester miscarriages are often caused by problems with the chromosomes of the foetus.

Chromosome problems

Chromosomes are blocks of DNA. They contain a detailed set of instructions that control a wide range of factors, from how the cells of the body develop to what colour eyes a baby will have.

Sometimes something can go wrong at the point of conception and the foetus receives too many or not enough chromosomes. The reasons for this are often unclear, but it means the foetus will not be able to develop normally, resulting in a miscarriage.

This is very unlikely to recur. It does not necessarily mean there's any problem with you or your partner.

Placental problems

The placenta is the organ linking the mother's blood supply to her baby's. If there's a problem with the development of the placenta, it can also lead to a miscarriage.

Things that increase your risk

An early miscarriage may happen by chance. But there are several things known to increase your risk of problems happening.

The age of the mother has an influence:

  • in women under 30, 1 in 10 pregnancies will end in miscarriage
  • in women aged 35 to 39, up to 2 in 10 pregnancies will end in miscarriage
  • in women over 45, more than 5 in 10 pregnancies will end in miscarriage

A pregnancy may also be more likely to end in miscarriage if the mother:

  • is obese
  • smokes
  • uses drugs
  • has lots of caffeine
  • drinks alcohol

Second trimester miscarriages

Long-term health conditions

Several long-term (chronic) health conditions can increase your risk of having a miscarriage in the second trimester, especially if they’re not treated or well controlled.

These include:

Infections

The following infections may also increase your risk:

Food poisoning

Food poisoning, caused by eating contaminated food, can also increase the risk of miscarriage. For example:

  • listeriosis – most commonly found in unpasteurised dairy products, such as blue cheese
  • toxoplasmosis – which can be caught by eating raw or undercooked infected meat
  • salmonella – most often caused by eating raw or partly cooked eggs

Read more about foods to avoid in pregnancy.

Medicines

Medicines that increase your risk include:

  • misoprostol – used for conditions such as rheumatoid arthritis
  • retinoids – used for eczema and acne
  • methotrexate – used for conditions such as rheumatoid arthritis
  • non-steroidal anti-inflammatory drugs (NSAIDs) – such as ibuprofen; these are used for pain and inflammation

To be sure a medicine is safe in pregnancy, always check with your doctor, midwife or pharmacist before taking it.

Read more about medicines during pregnancy.

Womb structure

Problems and abnormalities with your womb can also lead to second trimester miscarriages. Possible problems include:

  • non-cancerous growths in the womb called fibroids
  • an abnormally shaped womb

Weakened cervix

In some cases, the muscles of the cervix (neck of the womb) are weaker than usual. This is known as a weakened cervix or cervical incompetence.

A weakened cervix may be caused by a previous injury to this area, usually after a surgical procedure. The muscle weakness can cause the cervix to open too early during pregnancy, leading to a miscarriage.

Polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a condition where the ovaries are larger than normal. It's caused by hormonal changes in the ovaries.

PCOS is known to be a leading cause of infertility as it can lower the production of eggs. There's some evidence to suggest it may also be linked to an increased risk of miscarriages in fertile women.

Misconceptions about miscarriage

An increased risk of miscarriage is not linked to:

  • a mother's emotional state during pregnancy, such as being stressed or depressed
  • having a shock or fright during pregnancy
  • exercise during pregnancy – but discuss with your GP or midwife what type and amount of exercise is suitable for you during pregnancy
  • lifting or straining during pregnancy
  • working during pregnancy – or work that involves sitting or standing for long periods
  • having sex during pregnancy
  • travelling by air
  • eating spicy food

Recurrent miscarriages

Many women who have a miscarriage worry they'll have another if they get pregnant again. But most miscarriages are a one-off event.

About 1 in 100 women experience recurrent miscarriages (3 or more in a row) and many of these women go on to have a successful pregnancy.

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Diagnosis

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What happens?

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Afterwards

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Prevention

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The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website nhs.uk
Last Updated: 07/05/2021 12:57:36