NT Scan Results: What Does a Higher-Chance Result Mean?

NT scan results describe the nuchal translucency, a measurement of fluid under the skin at the back of the baby's neck, taken by ultrasound at around 11 to 14 weeks. The measurement is usually combined with a blood test and your age to give a chance, such as 1 in 300, that the baby has Down's, Edwards' or Patau's syndrome. It is a screening result, not a diagnosis.

This guide explains how to read the number, what a higher-chance result can lead to and how to prepare for the conversation with your team. Screening and any further testing are choices, and there is no single right decision.

Waiting for screening results can be stressful, but some symptoms need help straight away whatever the result. Contact your maternity unit, early pregnancy unit or local emergency services if you have:

• Heavy vaginal bleeding, such as soaking a pad soon after putting it on.
• Severe tummy pain, or pain in the shoulder.
• Feeling faint, dizzy or very unwell, or passing out.
• Later in pregnancy, your baby moving less than usual or a change in their usual pattern of movements. The NHS says to call immediately, not the next day.

All babies have some fluid at the back of the neck in early pregnancy. MedlinePlus explains that babies with Down syndrome and some other conditions tend to have more fluid, so the area can look thicker on the scan. Extra fluid has also been linked with some heart conditions.

MedlinePlus notes that a measurement up to about 3 mm is generally considered lower risk, but clinics may use different cut-offs. In many screening programmes the NT measurement is not interpreted alone. It is combined with other information to give an overall chance.

In the NHS combined test, the NT measurement is combined with a blood test for two pregnancy hormones, free beta hCG and PAPP-A, and with your age. The blood test is taken between 10 and 14 weeks and the scan between 11 and 14 weeks.

If the scan happens after 14 weeks, the NHS offers a different blood test, the quadruple test, between 14 and 20 weeks. It screens only for Down's syndrome and is not as accurate as the combined test.

Sometimes a low PAPP-A level is reported even when the overall chance is low. That relates to placenta function rather than the chromosomal conditions. See our guide to low PAPP-A in pregnancy.

The result is written as 1 chance in a number. The bigger the second number, the smaller the chance. So 1 in 1,000 is a smaller chance than 1 in 200.

In England, a result anywhere up to 1 in 150, such as 1 in 100, is called higher chance. A result of 1 in 151 or lower, such as 1 in 300, is called lower chance. Other countries and laboratories may use different cut-offs and wording. GOV.UK says around 3 in every 100 results are higher chance.

Most people receive a lower-chance result. The NHS usually sends this by letter, with results typically within about 2 weeks of the test. NHS genomics guidance says no further action is needed after a lower-chance result. Even so, screening can miss some affected pregnancies, so a lower-chance result is reassuring rather than a guarantee. If anything on a later scan raises a question, your team will discuss it with you.

In the NHS you should be contacted within about a week to discuss the result and your options. GOV.UK says most women with higher-chance results go on to have a baby without any of the conditions. The usual options are:

• No further testing. This is a valid choice.
• NIPT (non-invasive prenatal testing), also called cell-free DNA or cfDNA screening. This is a blood test from the pregnant person that looks at DNA fragments from the placenta. It is more accurate than the combined test but it is still screening, so a higher-chance NIPT result needs a diagnostic test to confirm. It is less accurate in twin pregnancies and for Edwards' and Patau's syndromes, and occasionally gives no result.
• A diagnostic test: chorionic villus sampling (CVS), usually at 11 to 14 weeks, or amniocentesis, usually after 15 weeks. These give a definite answer. GOV.UK says about 1 in 200 people who have a diagnostic test will miscarry because of it.
• Further detailed ultrasound in a specialist fetal medicine unit may also be offered, depending on the scan findings.

It is fine to take time, bring someone with you and ask for things to be explained again.

• What was my exact chance for each condition, and what NT measurement was recorded?
• Was anything else noted on the scan, and will I be offered a more detailed scan?
• What would NIPT tell me that the combined test did not, and what are its limits for my pregnancy?
• How soon would NIPT or a diagnostic test give results, and how would I be told?
• What are the risks of CVS or amniocentesis at my clinic?
• How long do I have to decide, and can I change my mind?
• Who can I contact for support while I decide?

A higher-chance result can bring up strong feelings, and people make different decisions for different reasons. Your antenatal screening midwife can talk through the options without pressure. In the UK, the NHS points to Antenatal Results and Choices (ARC), a charity that gives independent information and support about screening and results. Similar services exist in other countries; ask your team what is available locally.

On SameCase, patients and verified doctors share de-identified cases. Reading how others approached a higher-chance screening result, such as what they asked about NIPT or diagnostic tests, can help you prepare your own questions. Every pregnancy and every decision is different. Other cases cannot predict your result or tell you what to choose, and your own care team remains your guide.