A miscarriage is the loss of a pregnancy that happens sometime during the first 23 weeks. The majority of miscarriages happen during the first 12 weeks of pregnancy, which is often referred to as the first trimester. The main symptom of a miscarriage is vaginal bleeding.

How common are miscarriages?

Miscarriages are much more common than most people realise. This may be because many women who have had a miscarriage prefer not to talk about it.

An estimated 20% of pregnancies end in miscarriage, although the figure could be significantly higher because many miscarriages are thought to occur before a woman realises that she is pregnant.

It is thought that most miscarriages are the result of random variations in the chromosomes of the baby. Chromosomes are genetic 'building blocks' that guide the development of a baby. If a baby has too many or not enough chromosomes, the pregnancy can end in miscarriage.


While a miscarriage does not usually seriously affect a woman's physical health, it can have a significant emotional impact. Many couples experience feelings of loss and grief.

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

Recurrent miscarriages (the loss of three or more pregnancies in a row) are uncommon and affect 1% of all couples. Even in the case of recurrent miscarriages, an estimated 75% of women go on to have a successful pregnancy in the future.


The most common symptom of miscarriage is vaginal bleeding, which can vary from light spotting to heavy bleeding.

It is important to realise that light vaginal bleeding is common during the first trimester of pregnancy, so having this symptom does not necessarily mean that you have had a miscarriage.

Other symptoms of a miscarriage include:

  • cramping and pain in your lower abdomen,
  • a discharge of fluid and/or tissue from your vagina, and
  • no longer experiencing the symptoms of pregnancy, such as nausea and breast tenderness.

When to seek medical help

See your GP if you experience vaginal bleeding and/or discharge. These symptoms do not automatically mean that you have had a miscarriage, but they should always be investigated.

When to seek urgent medical help

On rare occasions, miscarriages happen because the pregnancy develops outside the womb. This is known as an ectopic pregnancy. Ectopic pregnancies are potentially serious because there is a risk that you could experience internal bleeding.

Symptoms of an ectopic pregnancy include:

  • heavy vaginal bleeding (soaking more than one sanitary pad every hour),
  • persistent and severe abdominal pain,
  • pain in your shoulder tip, and
  • feeling very faint and light-headed.

If you experience any of the symptoms above, visit your local accident and emergency (A&E) department immediately.

See Useful links, for more information about ectopic pregnancy.


Ectopic refers to a pregnancy that occurs outside the womb, most commonly in the fallopian tubes.
The uterus, or womb, is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy.
Nausea is when you feel like you are going to be sick.
Pain is an unpleasant physical or emotional feeling and your body's way of warning you it has been damaged.
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Discharge is when a liquid, such as pus, oozes from a part of your body.
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.  

If a miscarriage happens during the first trimester of pregnancy (the first three months), it is usually due to problems with the foetus (the unborn baby).

If a miscarriage happens during the second trimester of pregnancy (between weeks 14 and 26), it is usually the result of an underlying health condition in the mother.

First trimester miscarriages 

Most first trimester miscarriages are caused by problems with the chromosomes of the foetus.

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.

For a pregnancy to be successful, a foetus needs 46 chromosomes: 23 are from the father's sperm and 23 are from the mother's egg.

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 that the foetus will not be able to develop normally, resulting in a miscarriage.

Risk factors

Problems with chromosomes often happen by chance. However, a number of known risk factors increase the chances of these problems occurring.


The most important risk factor for miscarriage is probably the age of the mother:

  • Women under 25 have a 9% risk of having a miscarriage.
  • Women between 25 and 29 have an 11% risk of having a miscarriage.
  • Women between 30 and 34 have a 15% risk of having a miscarriage.
  • Women between 35 and 39 have a 25% risk of having a miscarriage.
  • Women between 40 and 44 have a 51% risk of having a miscarriage.
  • Women over 45 years have a 75% risk of having a miscarriage.

Other risk factors

Other risk factors for having a miscarriage include:

  • obesity,
  • smoking during pregnancy,
  • drug misuse during pregnancy (particularly cocaine),
  • drinking more than 200mg of caffeine a day (equivalent of two mugs of tea or instant coffee, one mug of filter coffee or five cans of cola), and
  • drinking more than two standadard drinks of alcohol a week (one standard drink is half a pint of beer or ordinary strength lager, a small glass of wine or a pub measure of spirits).

Second trimester miscarriages

Chronic health conditions

There are a number of chronic (long-lasting) health conditions that can increase the risk of having a miscarriage. These are:

  • diabetes (if it is poorly controlled),
  • severe high blood pressure (hypertension),
  • lupus (a condition where the immune system attacks healthy tissue),
  • kidney disease, and
  • an overactive or underactive thyroid gland.


There are a number of infections that may increase the risk of having a miscarriage. These include:

  • rubella (German measles),
  • cytomegalovirus (CMV), and
  • toxoplasmosis (a bacterial infection).

Miscarriage can also be caused by a bacterial infection of the vagina. This type of infection is known as bacterial vaginosis (BV).


Antibodies are proteins that are produced by the immune system to fight infection.

Approximately 15% of women with a history of recurrent miscarriages (three or more miscarriages in a row) have a higher than usual level of an antibody called antiphospholipid (aPL) in the blood. The aPL antibodies are known to cause blood clots. These blood clots can block the supply of blood to the foetus, which can cause a miscarriage.

Having a high number of aPL antibodies in your blood is known as Hughes syndrome. See Useful links for more information about Hughes syndrome.

Womb structure

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

  • fibroids (non-cancerous growths in the womb), and
  • scarring on the surface of the womb.

Weakened cervix

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

The muscle weakness can cause the cervix to open too early during pregnancy, leading to a miscarriage.


Prolactin is a hormone that is produced during pregnancy. It helps prepare the breasts for breastfeeding. Sometimes, women have a higher level of prolactin in their body than usual. This is known as hyperprolactinaemia.

Some limited evidence suggests that hyperprolactinaemia may be linked to an increased risk of miscarriage.

Polycystic ovary syndrome

Polycystic ovary syndrome (POS) is a condition where the ovaries are larger than normal. It can lead to hormonal imbalances inside the womb.

POS is known to be a leading cause of infertility. There is some evidence to suggest that it may also be linked to an increased risk of miscarriage in women who are still fertile.

However, the exact role that POS plays in miscarriages is unclear.

Misconceptions about miscarriage

There are a number of widely held assumptions about the possible causes of miscarriages. For example, maternal stress is often believed to be a cause. However, there is no evidence to support such claims.

An increased risk of miscarriage is also 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 what type of exercise is suitable for you during pregnancy with your GP or midwife),
  • lifting or straining during pregnancy,
  • working during pregnancy, and
  • having sex during pregnancy.


Chromosomes are the parts of a cell that carry genes. A human cell usually has 23 pairs of chromosomes.
The uterus, or womb, is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy.
Constipation is when you pass stools less often than usual or when you have difficulty going to the toilet because your stools are hard and small.
Genetic refers to genes, the characteristics inherited from a family member.

A number of tests can confirm whether your pregnancy has ended and you have had a miscarriage. The tests can also confirm whether:

  • you have had an incomplete miscarriage, where there is still some feotal tissue left in your womb, or
  • you have had a complete miscarriage, where all the foetal tissue has been passed out of your womb.

The tests include:

  • blood and urine tests, which can be used to measure a hormone associated with pregnancy called beta hCG,
  • ultrasound, and
  • a pelvic examination.

Recurrent miscarriages

If you have had recurrent miscarriages (three or more miscarriages in a row), further tests can check if there is an underlying cause. However, some of these tests can only be used if you become pregnant again. These further tests are outlined below.


If you have had recurrent miscarriages, you and your partner can be tested for abnormalities in your chromosomes that could be causing the problem. This is known as karyotyping.

If karyotyping detects problems with your or your partner's chromosomes, you can be referred to a clinical geneticist (gene expert). They will be able to explain what the chances of you having a successful pregnancy in the future are and whether there are any fertility treatments, such as IVF, that you could try. This type of advice is known as genetic counselling.

Pelvic ultrasound

A pelvic ultrasound can be used to check the structure of your womb for any abnormalities. The procedure involves using an ultrasound scanner to study your lower abdomen and pelvis.

Vaginal ultrasound

A vaginal ultrasound can check if you have a weakened cervix. This test can usually only be carried out if you become pregnant again.

A vaginal ultrasound is similar to a pelvic ultrasound but in this procedure a small piece of equipment, known as a transducer, is inserted into your vagina. This produces more detailed scan of your cervix. The procedure can feel a little uncomfortable but is not painful.

Blood testing

Your blood can be checked to see whether you have high levels of the hormone prolactin and/or the antiphospholipid (aPL) antibody. Testing for prolactin can only be done if you become pregnant again.


Your treatment plan

Your treatment plan depends on whether you have had a complete or incomplete miscarriage (whether there is any foetal tissue left in your womb).

If you have had a complete miscarriage, no further medical treatment is required.

If you have had an incomplete miscarriage, it will be necessary to remove the foetal tissue as there is a risk that it could become infected. This can be done in three ways:

  • surgical treatment, where minor surgery is used to remove the tissue,
  • medical treatment, where medication is used to remove the tissue, or
  • expectant treatment, where you wait for the tissue to pass naturally out of your womb.

All three treatments are equally effective in preventing infection.

Medical and expectant treatments sometimes fail to remove all the foetal tissue or can cause other complications. This means that there is a slightly higher risk that you will need further unplanned surgery.

Discuss the treatment options with the doctor in charge of your care.

Surgical treatment

Surgery usually takes place within a few days of a miscarriage. However, there are a number of circumstances where you may be advised to have immediate surgery, including:

  • if you experience continuous heavy bleeding,
  • if there is evidence that the foetal tissue has become infected, or
  • if medical and expectant treatments have previously been unsuccessful.

Surgery is usually performed under general anaesthetic. Your cervix will be opened with a small tube, known as a dilator, and the tissue will be removed using a suction device. This type of surgery is known as evacuation of retained products of conception (ERPC).

Before surgery, you may be given medication to soften the cervix and to make it easier to perform the surgery.

ERPCs are usually very safe. However, as with all surgery, there is a small risk of complications.

Complications of ERPC include:

  • infection,
  • excessive bleeding, and
  • the womb being torn during the procedure (which would require surgery to repair it).

In 95% of cases, surgical treatment is successful in removing foetal tissue.

Medical treatment

Medical treatment for miscarriage involves taking tablets that cause the cervix to open, allowing the tissue to pass out. The tablets can either be swallowed or inserted directly into your vagina (pessaries), where they dissolve.

The effects of the tablets usually begin within a few hours. You will experience symptoms similar to a heavy period, such as cramping and heavy vaginal bleeding. You may also experience some further vaginal bleeding for up to three weeks.

Medical treatment is successful in removing foetal tissue in 85% of cases. However, you will need to have surgery if the treatment is unsuccessful.

Expectant treatment

If you have expectant treatment, it may be some time before you experience vaginal bleeding. The bleeding tends to be heavier than your usual period and you may also experience cramping. Bleeding can last for up to three weeks.

If the bleeding becomes particularly heavy or you experience severe pain, contact your hospital as soon as possible. You should be given a 24-hour helpline number to call in case of emergency.

Expectant treatment is successful in removing foetal tissue in 50% of cases. If treatment is unsuccessful, you will need either medical or surgical treatment.

After your treatment

Once your treatment has finished, you can decide what happens with the remains of your pregnancy. Some women prefer to leave the decision to the hospital staff whereas others prefer to discuss the available options. Hospital staff can advise you about arranging a religious service and about burial or cremation.

The cremation of foetal tissue does not provide any ashes for you to scatter.

Treating recurrent miscarriages

Hughes syndrome

Currently, Hughes syndrome is the only cause of recurrent miscarriage that can be successfully treated.

Research has shown that a combination of aspirin and heparin (a medicine that is used to prevent blood clots) can improve pregnancy outcomes in women with Hughes syndrome. About 74% of women who receive this type of treatment go on to have a successful pregnancy.

Suggested treatments

A number of other suggested treatments for recurrent miscarriages have been studied. These include:

  • hormone treatments during pregnancy,
  • using specially modified antibodies during pregnancy, and
  • taking vitamin supplements during pregnancy.

The results of all these studies have been disappointing and there is no evidence that these treatments can prevent miscarriages.


Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.  
Ultrasound scans are a way of producing pictures of inside the body using sound waves.
The uterus, or womb, is a hollow, pear-shaped organ in a woman where a baby grows during pregnancy.
Ectopic refers to a pregnancy that occurs outside the womb, most commonly in the fallopian tubes.
The heart is a muscular organ that pumps blood around the body.

Emotional impact

A miscarriage can have a profound emotional impact, not only on a woman but also on her partner, friends and family. Sometimes, the emotional impact is felt immediately after the miscarriage, whereas in other cases it can take several weeks to emerge.

The most common emotions that are felt after a miscarriage are grief and bereavement. They can cause physical and emotional symptoms.

Physical symptoms of grief and bereavement include:

  • fatigue (tiredness),
  • loss of appetite,
  • difficulties concentrating, and
  • sleeping problems.

Emotional symptoms of grief and bereavement include:

  • guilt,
  • shock and numbness,
  • anger (sometimes at a partner, or at friends or family members who have had successful pregnancies), and
  • an overwhelming sense of sadness.

Different people grieve in different ways. Some people find it comforting to talk about their feelings while others find the subject too painful to discuss.

Some women come to terms with their grief after a few weeks of having a miscarriage and start planning for their next pregnancy. For other women, the thought of planning another pregnancy is too traumatic, at least in the short term.

If you are worried that you or your partner are having problems coping with grief, you may need further treatment and counselling. There are a number of support groups that can provide or arrange counselling for people whose lives have been affected by miscarriage. See Useful links for more information.

Alternatively, your GP should be able to provide you with support and advice.


Even if you take the best care of yourself during pregnancy, you often can't prevent a miscarriage.

However, there are ways to lower your risk of miscarriage:

  • do not smoke during pregnancy,
  • do not drink alcohol during pregnancy,
  • do not use illegal drugs during pregnancy,
  • drink at least 1.2 litres (six to eight glasses) of fluids, such as water and fruit juice, every day, and
  • eat a healthy, balanced diet with at least five portions of fruit and vegetables a day.

See Useful links for more information about antenatal health and care.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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