The short answer
Get the full report, note which condition was flagged and how often that particular result turns out to be right, and ask for genetic counselling. A detailed scan may add information, but a normal scan does not cancel the result. Confirming it almost always needs CVS or amniocentesis. Because NIPT mostly reads placental DNA rather than the baby's, no irreversible decision should rest on the screening result alone.
First, turn the report into one sentence
Do not rely on a phone message saying “the NIPT was positive”. Get the actual report and find:
- which chromosome or condition was flagged;
- the exact wording — high risk, suspected, atypical, or no result;
- how often this kind of result turns out to be correct, if the laboratory gives a figure;
- the fetal fraction and any notes about sample quality;
- whether there was a twin that stopped developing, an egg donor, or anything else the laboratory needed to know.
These lead to genuinely different next steps. An unusual or atypical finding is not the same as a straightforward high-risk trisomy result, and a no-result test is not a positive one.
How often is a high-risk result actually right?
This is the question that matters most, and it is not the same as “how accurate is the test”.
Think of it this way: out of 100 people with this same high-risk result, how many are carrying a baby with the condition? For the common conditions, and for people who already had a higher starting chance, that proportion is high. For rare conditions on expanded panels, it can be surprisingly low — sometimes most high-risk results turn out to be false alarms.
A headline claiming a test is “over 99% accurate” is usually describing something else entirely: how good the test is at picking up the condition when it is genuinely there. That is a different question from the one you are asking now.
Ask your clinician for the figure that applies to your result, your condition and your situation.
Why false alarms happen
NIPT mostly reads DNA from the placenta. A high-risk signal can come from:
- a chromosome condition present in both the placenta and the baby;
- a change present in the placenta but not in the baby;
- a twin that stopped developing very early;
- a chromosome difference in the pregnant person;
- less commonly, a technical or other biological reason.
The laboratory result by itself often cannot tell these apart.
The next steps, in order
| Step | What it adds |
|---|---|
| Review with genetics or fetal medicine | How likely this result is to be real, and which confirming test fits |
| Detailed ultrasound | Looks for physical findings, and helps choose timing and procedure |
| CVS | An earlier diagnostic sample, taken from the placenta |
| Amniocentesis | A later diagnostic sample, taken from the fluid around the baby |
| Condition-specific counselling | What life with the condition can actually look like, if it is confirmed |
Both NIPT and CVS involve placental material, in different ways. For some results, amniocentesis answers more cleanly whether the finding is really in the baby. For others, CVS is a reasonable earlier route. The choice is specific to your result and your scan.
A normal scan does not erase the result
Some chromosome conditions usually show something on ultrasound; others may show nothing at the time of the scan. A normal scan can change the overall picture, but it cannot prove the NIPT was a false alarm.
The same applies the other way round. Something unusual on a scan is not confirmation either. Only a diagnostic test connects a screening result to a definite answer.
Questions worth asking before a procedure
- How likely is this result to be right, in my situation?
- Could this finding be confined to the placenta?
- Which procedure is available at the number of weeks I am now?
- Which laboratory test will be run on the sample?
- How long will the rapid result take, and how long the full one?
- What would a positive, a negative or an uncertain result still leave unanswered?
The waiting is horrible. But there is usually enough time to work out which test will give the cleanest answer. A screening report should open the conversation, not end it.
Sources and further reading
Common questions
- Does a high-risk NIPT mean the baby definitely has the condition?
- No. It means the chance is above the screening threshold. How often it is confirmed varies a great deal with the condition, your starting chance and the details of the result.
- Can I just repeat the NIPT?
- A second screening test usually cannot explain why the first one was positive. When a definite answer matters, CVS or amniocentesis is the route.
- Can an ultrasound confirm it?
- It can find features that raise or lower concern, but neither a normal nor an abnormal scan can replace a chromosome test.
- CVS or amniocentesis — which is better after a positive NIPT?
- It depends on how many weeks pregnant you are, which chromosome was flagged, what the scan shows, and whether the finding might be limited to the placenta. A fetal medicine or genetics service can say which sample answers your question best.
- How long will I be waiting?
- A rapid result on a diagnostic sample often comes back within a few days, with fuller results later. Ask for the expected timing when the procedure is booked — the waiting is easier when you know how long it should be.