Tests
explained
All pregnant women in the UK are offered antenatal screening tests*. It is always your choice to have a screening test.
Screening tests are not harmful to your baby but they can lead to decisions about tests that do carry a risk to your pregnancy.
Diagnostic tests such as CVS and amniocentesis carry a small risk (approximately 0.5% or 1 in 200) of causing a miscarriage which means the decision about whether to have them can be difficult. Unfortunately, there is no other way of knowing for sure whether your baby has Down’s syndrome, Patau’s syndrome, Edwards’ syndrome and certain other genetic conditions.
*The types of screening tests offered to women may vary across the four countries of the UK.
Northern Ireland
Northern Ireland does not have a standardised national programme of antenatal screening for fetal anomalies. The screening offered to women will vary between hospitals. Find out more here.
What is the difference between a screening and a diagnostic test?
- A screening test in pregnancy cannot give you a yes/no answer as to whether your baby has a condition. It can only tell you what the chances are of your baby being affected. Screening tests in pregnancy include blood tests and ultrasound scans**.
- A diagnostic test in pregnancy can tell you for definite whether your baby has a condition or not. Diagnostic tests in pregnancy include CVS, amniocentesis and ultrasound scans*.
**ultrasound scans can suggest there might be a condition (as in screening for Down’s syndrome) or confirm there is a condition (as in diagnosing spina bifida).
All tests should be fully explained to you by your doctor or midwife before you have them.
Timing of antenatal screening and diagnostic tests
Fetal viability ultrasound scan...
Find out more ⟶Screening for Down’s syndrome, Edwards’ syndrome and Patau’s syndrome
Screening tests for these three conditions are non-invasive tests which are offered to all pregnant women in the UK...
Find out more ⟶Diagnostic tests
Invasive diagnostic tests (CVS and amniocentesis) can tell you for certain if your baby has a chromosomal condition...
Find out more ⟶MRI scans
Magnetic resonance imaging (MRI) is a type of scan that uses a large magnet, pulses of radio waves, and a computer to create images of your baby...
Find out more ⟶Prenatal genetic screening tests
All women in England, Scotland and Wales are offered screening tests for Down’s syndrome, Edwards syndrome and Patau’s syndrome and sickle cell disease and thalassaemia...
Find out more ⟶Prenatal genetic testing and multiple pregnancies
Expecting twins, triplets or higher multiples affects the genetic test options in a pregnancy. Parents in these circumstances...
Find out more ⟶