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. If you're less than 6 weeks pregnant, you may not be referred for tests straight away. This is because it's very hard to confirm a miscarriage this early on.

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 is not painful.

You may be able to have an external scan of 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 do not increase your risk of miscarriage.

You may also be offered blood tests to measure hormones associated with pregnancy. You usually need to have 2 blood tests 48 hours apart to see if your hormone levels go up or down.

Recurrent miscarriages

If you've had 3 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. 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 a third miscarriage, it's recommended that the foetus is tested for abnormalities in the chromosomes (blocks of DNA).

If a genetic abnormality is found, you and your partner can also be tested for abnormalities with your chromosomes that could be causing the problem. This type of testing is known as karyotyping.

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 tummy and pelvis to provide a more accurate diagnosis.

Blood testing

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

These aPL antibodies are known to increase the chance of blood clots and change 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.