The second screening test is another blood test called NIPT (non-invasive prenatal testing). NIPT is more accurate than the combined or quadruple test, though it is not quite as accurate in twin pregnancies. It works by measuring DNA (genetic material) in your blood. Some of this DNA will be from the baby’s placenta. If there is more DNA than expected from chromosomes 21, 18 or 13 it may mean that your baby has Down’s syndrome, Edwards’ syndrome or Patau’s syndrome. Like every screening test, though, it does not give a definite answer. NIPT cannot harm your baby. Most women will get their result within 2 weeks.

Most people will get a lower-chance result, meaning your chance of having a baby with the condition is low. You will not be offered a diagnostic test.

If your NIPT result shows a higher-chance result then the chance of your baby having the condition is high. You will then be offered a diagnostic test, though it is up to you whether or not to have this. In a small number of cases, NIPT might produce no result. You can then choose between one further NIPT, a diagnostic test or no further testing.