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Screening in pregnancy

Every pregnant woman in England should be offered screening in pregnancy, however to access these it is important to attend antenatal services early in pregnancy. Information is available in the NHS "Screening tests for you and your baby" booklet which can be obtained from the midwives at your health centre.  

The NHS fetal anomaly screening programme (FASP) offers screening for fetal anomalies, Down's syndrome (also known as Trisomy 21 or T21), Edwards' syndrome (Trisomy 18/T18) and Patau's syndrome (Trisomy 13/T13).


Screening for Down's, Edwards' and Patau's syndromes in pregnancy in the South West Region

A screening test for these conditions, called the first trimester "combined test", is available between 10 and 14 weeks of pregnancy. If you choose to have the combined test, a blood sample is taken from you. At the dating ultrasound scan the fluid at the back of the baby's neck is measured (known as the nuchal translucency). The information from these 2 tests is combined to work out the risk (how likely it is) of the baby having Down's, Edwards' or Patau's syndrome.

You can choose to have screening for:

  • Down's, Edwards' and Patau's syndromes
  • Down's syndrome only
  • Edwards' and Patau's syndromes only
  • none of the conditions

If you are too far on in your pregnancy to have the combined test for Down's syndrome, you will be offered a blood test between 14 and 20 weeks of pregnancy. This test is not quite as accurate as the combined test. If you are too far on in your pregnancy to have the combined test for Edwards' and Patau's syndromes, you will be offered a mid-pregnancy scan which will look for physical abnormalities.

The screening test cannot harm you or the baby but it is important to consider carefully whether to have this test or not. This test cannot tell you if the baby definitely has Down's, Edwards' or Patau's syndromes or not. The screening test can provide information that may lead to further important decisions. For example, you may be offered diagnostic tests that have a risk of miscarriage.

For further information:


Mid-pregnancy anomaly scan

The scan will look in detail at the baby's bones, heart, brain, spinal cord, face, kidneys and abdomen. It usually takes place between 18 weeks, and 20 weeks and 6 days of pregnancy.

In most cases the scan will show that the baby appears to be developing as expected but sometimes a problem is found or suspected. Some problems can be seen more clearly than others.

For further information:


Other screening tests in pregnancy

Sickle cell & thalassaemia screening is a blood test offered in early pregnancy to find out if you are a carrier of the sickle cell or thalassaemia gene and therefore likely to pass it on to the baby. All pregnant women are offered a test for thalassaemia but not all women are automatically offered a test for SCD. The screening offered depends on where you live. If you are a carrier of a haemoglobin disease, the baby's father will be offered a blood test. If the baby's father is also a carrier you will be offered diagnostic tests to find out if the baby is affected.

For further information:

Some private companies also provide screening tests that you have to pay for. The NHS cannot guarantee the quality of private screening. For further information contact Antenatal results & choices (Tel no.: 0845 077 2290 /

The screening midwives are Anne Duffner and Magda Wigram