Helpline: 0207 713 7486

Helpline: 0207 713 7486

Tests explained

All pregnant women in the UK are offered antenatal screening tests*. Most women will be reassured by the results but some (approximately 5%) will be given a result that leads to decisions about diagnostic testing.

It is always your choice to have any test.

Diagnostic tests such as CVS and amniocentesis carry a small risk (approximately 0.5% or 1 in 200) of 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 a chromosomal syndrome or certain other genetic conditions.

*The types of screening tests offered to women may vary across the four countries of the UK.

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 (such as NIPT) 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 decide whether to have them.

ARC's national helpline

Want to talk? We’re here as often as you need us. Our helpline is answered by trained staff Monday to Friday, 10.00am-5.30pm call 0207 713 7486.