If you see your GP or midwife because of vaginal bleeding or other symptoms of miscarriage, you may be referred to an early pregnancy unit at a hospital for tests. 

If you're more than 18 weeks pregnant, you'll usually be referred to the maternity unit at the hospital.

Tests

The hospital can carry out tests to confirm whether you're having a miscarriage. The tests can also confirm whether there's still some pregnancy tissue left in your womb (an incomplete or delayed miscarriage) or if all the pregnancy tissue has been passed out of your womb (a complete miscarriage).

The first test used is usually an ultrasound scan to check the development of your baby and look for a heartbeat. In most cases, this is usually carried out using a small probe inserted into the vagina (transvaginal ultrasound). This can feel a little uncomfortable but isn't painful.

You may be able to have an external scan through your tummy if you prefer, although this method reduces the accuracy of the scan. Neither type of scan is dangerous to the baby and they don't increase your risk of miscarriage.

You may also be offered blood tests to measure hormones associated with pregnancy, such as beta-human chorionic gonadotropin (hCG) and progesterone. These may be repeated after 48 hours if:

• the levels are borderline
• the scan isn't conclusive
• it's very early in your pregnancy

Sometimes a miscarriage can't be confirmed immediately using ultrasound or blood testing. For example, a heartbeat may not be noticeable if your baby is at a very early stage of development (less than six weeks). If this is the case, you may be advised to have a further ultrasound or pregnancy test, or both, again in a week or two.

Recurrent miscarriages

If you've had three or more miscarriages in a row (recurrent miscarriages), further tests are often used to check for any underlying cause. However, no cause is found in about half of cases. These further tests are outlined below.

If you become pregnant, most units offer an early ultrasound scan and follow-up in the early stages to reassure and support parents.

Karyotyping

If you've had recurrent miscarriages, you and your partner can be tested for abnormalities in your chromosomes (blocks of DNA) that could be causing the problem, which is the rarest of known causes. This type of testing 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'll be able to explain your chances of a successful pregnancy in the future and whether there are any fertility treatments, such as in vitro fertilisation (IVF), that you could try. This type of advice is known as genetic counselling.

Read more about genetic testing and counselling. 

Ultrasound scans

A transvaginal ultrasound can be used to check the structure of your womb for any abnormalities. A second procedure may be used with a 3D ultrasound scanner to study your lower abdomen and pelvis to provide a more accurate diagnosis.

The scan can also check if you have a weakened cervix. This test can usually only be carried out when you become pregnant again, in which case you'll usually be asked to come for a scan when you are between 10 and 12 weeks pregnant.

Blood testing

Your blood can be checked for high levels of the antiphospholipid (aPL) antibody and lupus anticoagulant. This test should be done twice, six weeks apart, when you're not pregnant.

Antiphospholipid (aPL) antibodies are known to increase the chance of blood clots and alter the way the placenta attaches. These blood clots and changes can reduce the blood supply to the foetus, which can cause a miscarriage.

Missed or delayed miscarriage

Sometimes a miscarriage is diagnosed during a routine scan carried out as part of your antenatal care. A scan may reveal your baby has no heartbeat, or that your baby is too small for the date of your pregnancy. This is called a missed or delayed miscarriage.