Prenatal Counseling · Atlanta Perinatal Associates
NIPT Result:
"No Call"
What this means, why it happens, and what we do next
Incomplete Result · Further Evaluation Recommended
What Is a "No-Call" Result?
When NIPT cannot produce an answer
❓
Not Positive
Not High-Risk
A no-call is not a positive NIPT result — it means the lab could not generate a result at all
⚗️
Not Negative
Not Low-Risk
A no-call is also not a reassuring result — we cannot say everything is normal
🔬
What It Is
Inconclusive
The lab analyzed your blood sample but did not have enough fetal DNA to report a reliable result
ℹ️

Other names for this result include "failed," "uninterpretable," "low fetal fraction," or "test inconclusive." All mean the same thing: NIPT could not give you an answer today.

How NIPT Works
Understanding what the lab is measuring
1
Blood draw from your arm
A sample of your blood contains tiny fragments of DNA — some from you, some from the placenta (representing your baby)
2
Lab separates fetal DNA from maternal DNA
The portion of DNA from the placenta is called the fetal fraction. Labs need at least ~4% fetal fraction to produce a reliable result
3
Lab counts chromosomes
With enough fetal DNA, the lab can estimate whether chromosomes 13, 18, 21, X, and Y are present in the expected amounts
4
No-call: fetal fraction too low to count reliably
When fetal DNA is scarce, the lab cannot distinguish a true chromosomal abnormality from normal variation — so it reports no result rather than an unreliable one
How Common Is a No-Call Result?
You are not alone — this happens regularly
1–8%
of all NIPT tests result in no call
(varies by lab and patient population)
✅
Good news
Most no-calls resolve with a repeat draw
Studies show 50–80% of repeat NIPT tests after an initial no-call will successfully return a result
⚠️
Important caveat
Risk of chromosomal differences is slightly higher
Fetuses with aneuploidy have lower average fetal fractions, so no-call results are slightly enriched for chromosomal conditions
💙

A no-call does not mean your baby has a problem. Most patients with this result have a healthy pregnancy. It means we need more information.

Why Did My Result Come Back "No Call"?
Common reasons fetal fraction is too low
⏱️
Most Common Reason
Early Gestational Age
Fetal fraction rises as pregnancy progresses. Tests drawn before 10 weeks may not have enough fetal DNA. Most labs recommend drawing at 10–12 weeks or later.
⚖️
Very Common Reason
High Maternal Body Weight
More maternal blood volume "dilutes" the fetal DNA percentage. BMI above 30–35 significantly increases no-call rates — this is a technical limitation, not a sign of a problem.
🧬
Less Common
Placental Factors
Confined placental mosaicism or placental irregularities can reduce fetal fraction. Rarely, a chromosomal abnormality in the fetus may itself lower fetal fraction (especially trisomy 18 and triploidy).
🔧
Occasionally
Technical / Lab Factors
Sample handling, shipping delays, or sequencing quality can affect the result. These are lab issues, not related to your baby's health.
What Does This Mean for Chromosomal Risk?
Putting the no-call result in clinical context
Situation Approximate Aneuploidy Risk Clinical Significance
Low-risk NIPT (negative screen) < 0.1% Highly reassuring; routine prenatal care
General population (no prior testing) 0.3–1% Background risk; depends on age & history
NIPT no-call result ~3–10% Elevated above background; warrants follow-up testing
High-risk NIPT (positive screen) Varies 20–90% Confirmatory diagnostic testing recommended
📊

Most studies place no-call aneuploidy risk below a positive NIPT result but above the general population baseline. The exact number for you depends on your age, ultrasound findings, and why the no-call occurred.

Norton et al., AJOG 2014 · Dar et al., Prenat Diagn 2014 · Quezada et al., Ultrasound Obstet Gynecol 2015
Option 1: Repeat the NIPT Blood Test
Often the first step for appropriate candidates
✅
Advantages
Non-invasive · Simple blood draw
No risk to the pregnancy. Most repeat draws succeed — fetal fraction increases naturally as pregnancy advances. Success rate is highest when the cause was early gestational age.
⏰
Timing
Usually 2–3 weeks after first draw
Waiting allows fetal fraction to rise. If high BMI is the cause, a repeat draw may still fail — diagnostic testing may be recommended instead to avoid further delays.
⚠
Important: Repeat NIPT is not always the best choice
If you are already at advanced gestational age, have additional risk factors (abnormal ultrasound, elevated maternal age, prior affected pregnancy), or have a second no-call result, your provider may recommend moving directly to diagnostic testing.
🗓️

If your repeat NIPT returns a negative (low-risk) result, that is significantly reassuring. If it returns a second no-call, further evaluation with diagnostic testing is typically recommended.

Option 2: Diagnostic Testing
CVS or amniocentesis — the only way to know for certain
🧬
Chorionic Villus Sampling (CVS)
10–13 Weeks
A thin needle samples placental tissue through the cervix or abdomen under ultrasound guidance. Results in 7–14 days. Procedure-related pregnancy loss risk: approximately 1 in 200–500.
💧
Amniocentesis
15–20 Weeks
A thin needle samples amniotic fluid through the abdomen under ultrasound guidance. Results in 7–14 days (FISH within 48 hrs). Procedure-related loss risk: approximately 1 in 500–1,000.
✅
Advantage
Definitive diagnosis
Chromosome analysis (karyotype or microarray) from fetal cells provides a diagnostic answer, not a screening result. Detects trisomies, deletions, duplications, and sex chromosome conditions.
⚠️
Trade-off
Small procedural risk
These are invasive procedures with a small but real risk of pregnancy loss. We will discuss whether this risk is appropriate based on your full clinical picture.
The Role of Ultrasound
What we look for and why it matters
👁
Nuchal translucency (NT) measurement — if 10–14 weeks
Fluid behind the baby's neck. An increased NT (≥ 3.0 mm) is associated with chromosomal abnormalities, heart defects, and other conditions. A normal NT is significantly reassuring.
❤️
Fetal cardiac anatomy
Chromosomal abnormalities — especially trisomy 18 and 21 — are commonly associated with heart defects visible on ultrasound. A normal cardiac view is reassuring.
📐
Fetal size and growth
Fetuses with chromosomal abnormalities (particularly trisomy 18 and triploidy) often measure smaller than expected. Normal growth is a positive finding.
🔍
Structural anatomy survey
At 18–20 weeks, a detailed anatomy scan evaluates all major organ systems. A normal anatomy scan provides strong reassurance, though it does not rule out chromosomal conditions entirely.
💡

Ultrasound and NIPT provide complementary information. Together, they give a more complete picture of your baby's health than either test alone.

Factors That Guide Your Next Step
We personalize the plan based on your full picture
📋
Factors Favoring Repeat NIPT
Lower-risk profile
  • Early gestational age at time of first draw
  • Normal anatomy ultrasound
  • Normal nuchal translucency
  • Younger maternal age
  • No prior chromosomal abnormality history
🏥
Factors Favoring Diagnostic Testing
Higher-risk profile
  • High maternal BMI (repeat NIPT likely to fail again)
  • Abnormal ultrasound findings
  • Increased nuchal translucency
  • Advanced maternal age (≥ 35)
  • Prior pregnancy with chromosomal abnormality
  • Second no-call result on repeat draw
🤝

There is no single right answer for everyone. We will talk through your specific situation together and support whatever decision feels right for you and your family.

What If I Choose to Decline Further Testing?
Your decision is respected — here is what we do instead
🔬
Enhanced Surveillance
Detailed Anatomy Scan
A thorough ultrasound at 18–20 weeks evaluates all major fetal structures. Many chromosomal conditions have recognizable features on ultrasound.
❤️
Fetal Cardiology
Fetal Echocardiogram
A dedicated cardiac ultrasound (fetal echo) provides a detailed look at the heart — often performed around 20–24 weeks when indicated.
📈
Growth Monitoring
Serial Growth Scans
Regular ultrasounds every 4–6 weeks to monitor fetal growth, which can be affected by chromosomal conditions.
💬

Choosing not to pursue diagnostic testing is a completely valid personal decision. Prenatal diagnosis does not change your pregnancy options — it only provides information, which some families want and others do not.

Your Action Plan
What happens next at Atlanta Perinatal Associates
1
Review your ultrasound findings today
We will review your most recent ultrasound together — nuchal translucency, anatomy, and fetal growth all inform next steps
2
Discuss your options and preferences
Repeat NIPT, CVS, amniocentesis, or surveillance-only — we will walk through the pros and cons of each in the context of your specific situation
3
Schedule your chosen next step
Whether a repeat blood draw or a diagnostic procedure, our team will coordinate the timing and logistics
4
Genetic counseling support
A certified genetic counselor can provide an in-depth discussion of risks, testing options, and results — we can make a referral if you would like one
🏥

Questions at any point? Call Atlanta Perinatal Associates. We are here to help you navigate this with clarity and care.

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