Can I still have the tests after 12 weeks?

Even if you start getting antenatal care later in pregnancy most of the tests that check your own health can be started whenever you begin. Some of the tests on the baby however are time dependent.

Most of the tests that check your own health can be started whenever you begin your antenatal care – even if it’s later in pregnancy.

Some tests on the baby to see if they are at risk of chromosomal conditions such as Down's, Patau's and Edwards' syndromes are done in the NHS at a certain point in their development. If you have missed these, you can pay privately for a different type of test as described below.

What tests need to be done at what stage?

The screening tests that are offered through the NHS to check whether your baby is at higher risk of conditions such as Down’s, Patau’s and Edwards’ syndrome can only be done at specific times in your pregnancy.

The combined test - 11-14 weeks

The ‘combined test’ needs to happen between 11-14 weeks of pregnancy and uses three factors to check risk:

  • a blood sample from you that measures two proteins
  • an ultrasound scan ( nuchal translucency scan) of your baby
  • your age.

During the scan the sonographer measures the fluid at the back of the baby’s neck. This measurement will change after 14 weeks plus one day.

The quadruple test - 14-20 weeks

If you have your booking appointment later in your pregnancy, your midwife can offer you the ‘quadruple test’. This test needs to happen between 14-20 weeks of pregnancy and uses two factors to check risk:

  • a blood test that measures four proteins
  • your age.

The quadruple test only tests for Down's Syndrome. For Patau’s and Edwards’ syndromes, you will be offered a mid-pregnancy scan that checks for physical abnormalities.

Can I get tested for conditions in any other way?

There is another screening test that is not available through the NHS but is offered in private clinics – it costs between £400 and £900. This is called the non-invasive prenatal screening test (NIPT). It can be carried out right until the end of pregnancy.

This test looks at the risk of Down’s syndrome and some other conditions and can be carried out from 10 weeks until the end of pregnancy.

It uses two factors to check risk:

  • an ultrasound scan to confirm the accurate dating of your pregnancy
  • a blood test from you – this examines the small amount of your baby’s fetal cells that can be found in your blood.

The result of this test is said to be highly accurate, but it does give a small number (0.3 percent) of false positives. A false positive is where it tells you that your baby has Down’s but this is not true. If you get a positive result, you’ll still need a diagnostic test, such as CVS or amniocentesis, to confirm the result for certain.

If you are interested in having the test at a private clinic, the charity Antenatal Results and Choices (ARC) suggests you check that the clinic has a clear link with an NHS unit. This means that there will be a co-ordinated care pathway in place if your test result is positive.

Read more midwives' answers

Sources

1.   NHS Choices [accessed 10 February 2015] ‘Screening for Down’s syndrome’ http://www.nhs.uk/conditions/pregnancy-and-baby/pages/screening-amniocentesis-downs-syndrome.aspx 

2.  Antenatal Results and Choices  [accessed 10 February 2015] ‘Non-Invasive Prenatal Testing (NIPT)’ http://www.arc-uk.org/tests-explained/non-invasive-prenatal-testing-nipt .

3.   NHS RAPID Project  [accessed 10 February 2015] ‘What is NIPT for Down syndrome?’ http://www.rapid.nhs.uk/guides-to-nipd-nipt/nipt-for-down-syndrome/.

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Last reviewed on April 1st, 2014. Next review date April 1st, 2017.

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