Sponsored by Myriad Genetics
There's sometimes a moment in early pregnancy when the list of recommended screens and tests can feel like a tidal wave. Between blood draws, ultrasounds, and paperwork, it's easy to nod along at your provider's office without fully understanding what each test is actually looking for.
Here's the short answer: Prenatal genetic screening can look for chromosomal abnormalities in your baby and inherited genetic conditions you or your partner might carry. These two main categories are worth understanding, because they do very different things.
What does prenatal genetic testing actually look for?
Prenatal screening evaluates your DNA from the pregnancy for chromosomal differences — things like Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13), as well as sex chromosome variations. Carrier screening tests you (and potentially your partner) to find out whether you carry gene changes for conditions like cystic fibrosis, sickle cell disease, Tay-Sachs disease, spinal muscular atrophy, Fragile X syndrome, and potentially hundreds of other inherited conditions, depending on the panel used.
One key distinction that trips a lot of people up: "screening" and "diagnostic" are not the same thing. Screening tests show your level of risk. They tell you whether something is more or less likely, not whether it's certain. Diagnostic tests — like chorionic villus sampling (CVS) or amniocentesis — provide definitive answers. Understanding that difference can save a lot of unnecessary panic.
The NIPT blood test: what it is and what it detects
NIPT stands for noninvasive prenatal testing, and it's become one of the most talked-about prenatal screens in recent years. The concept is surprisingly straightforward: during pregnancy, tiny fragments of your baby's DNA (called cell-free fetal DNA) circulate in your bloodstream. NIPT analyzes those fragments through a simple blood draw from your arm.
NIPT is available from about eight weeks of pregnancy onward, making it one of the earliest screening options. Its primary targets are the three most common trisomies:
Trisomy 21 (Down syndrome) — the most common chromosomal condition
Trisomy 18 (Edwards syndrome) — a more severe condition with significant developmental impacts
Trisomy 13 (Patau syndrome) — a rare and serious chromosomal condition
Beyond those three, NIPT can also detect sex chromosome differences like Turner syndrome and Klinefelter syndrome. Some expanded panels go further, screening for microdeletions such as DiGeorge syndrome (22q11.2 deletion). And yes, it can also reveal your baby's sex if you want to know.
NIPT is about 99% accurate in detecting Down syndrome. The test is slightly less accurate for detecting trisomy 18 and 13. But here's what can't be stressed enough: NIPT is a screening test, not a diagnostic one. A positive result means further testing is recommended, not that a diagnosis is confirmed.
How accurate is genetic screening like NIPT?
When you hear "99% accurate," it's natural to think that means the test is almost never wrong. But accuracy in genetic screening is more nuanced than a single number suggests.
There are two important metrics to understand. The detection rate (also called sensitivity) tells you how often the test correctly identifies a condition when it's truly present. The positive predictive value (PPV) tells you how likely it is that a positive result actually means your baby has the condition.
Several factors can also affect accuracy:
Gestational age: earlier testing may have less fetal DNA available
Maternal weight: higher BMI (body mass index) can dilute the fetal DNA fraction in your blood
Twin pregnancies: accuracy may be reduced with multiples
What's being screened: common trisomies are far more reliably detected than rare microdeletions
A "low-risk" result means the screening didn't find elevated risk. A "high-risk" result means an elevated probability that warrants follow-up, not a diagnosis. This is exactly why diagnostic testing exists as a next step.
Prenatal genetic screening vs. carrier screening: know the difference
This is where things can get confusing, so let's break it down simply. Prenatal genetic screening (like NIPT) looks at your baby for chromosomal conditions. Carrier screening looks for gene changes you might carry that could be passed on to your child.
Most carriers of recessive genetic conditions are healthy and have no known family history of the disease. That's what makes carrier screening so valuable: It reveals possibly hidden risks. If both you and your partner happen to carry a gene change for the same recessive condition, your baby has a 25% chance of being affected.
The typical scenario looks like this: You get carrier screening (before pregnancy or in the first trimester), and if you're found to be a carrier for something, your partner gets tested for that same condition. If you're both carriers, genetic counseling helps you understand your options.
Many pregnant people do both types of screening. Providers recommend it.
The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant individuals be offered NIPT regardless of baseline risk. In addition, ACOG advises that anyone considering pregnancy or those who are already pregnant be offered carrier screening for conditions such as cystic fibrosis and spinal muscular atrophy.
What conditions can be detected through genetic testing?
The list is longer than most people expect. Here's a breakdown by category.
Chromosomal conditions (detected via NIPT):
Microdeletions
Down syndrome (trisomy 21)
Edwards syndrome (trisomy 18)
Patau syndrome (trisomy 13)
Sex chromosome aneuploidies (Turner syndrome, Klinefelter syndrome, Triple X, XYY)
Conditions related to all other chromosomes
Single-gene disorders (detected via carrier screening) including (but not limited to):
Cystic fibrosis
Sickle cell disease
Spinal muscular atrophy
Tay-Sachs disease
Fragile X syndrome
Questions Women Are Asking
Myriad® Genetics offers comprehensive panels that screen for up to 274 conditions. Some conditions are more prevalent in certain ethnic backgrounds — Tay-Sachs in Ashkenazi Jewish populations, sickle cell disease in people of African descent — but expanded panels help ensure no one falls through the cracks based on ancestry alone.
It's also worth noting the limitations: Not all genetic conditions can be detected prenatally. Screening and even diagnostic testing cover a lot of ground, but they can't identify every possible condition.
How is genetic screening done? The actual process
If you're nervous about the testing itself, here's the reassuring part: it's simple. NIPT involves a standard blood draw from your arm. Carrier screening is either a blood draw or a saliva sample. No fasting, no special preparation, and zero risk to you or your baby.
Your sample gets sent to a lab — Myriad Genetics is one example of a lab partner that processes these tests — where the analysis happens behind the scenes. Then you wait.
How long does genetic screening take?
The waiting can feel like the hardest part. Here's a general timeline:
NIPT results: typically 7 to 14 days
Carrier screening results: around 2 to 3 weeks
If you haven't heard anything within the expected window, it's completely okay to call and ask for an update. Occasionally, results are delayed or require a repeat blood draw — this can happen with NIPT if the fetal DNA fraction in your sample was too low, which is more common with higher maternal BMI.
Genetic screening pros and cons: making the decision
Let's get one thing straight: there's no wrong answer here. Whether you choose to do all the testing, some of it, or none of it, that's a deeply personal decision.
Benefits of genetic screening
Peace of mind: The majority of results come back low-risk, which can ease a lot of first-trimester anxiety.
Time to prepare: Early detection gives you time to prepare emotionally, financially, and medically.
Informed pregnancy management: Results can guide your provider's care plan and delivery preparations.
Access to specialists: A positive result opens the door to genetic counseling and, if needed, diagnostic testing like CVS or amniocentesis.
Empowered decision-making: Information puts you in the driver's seat.
Limitations and considerations
Screening shows probability, not certainty.
False positives can cause anxiety during an already emotional time.
Not every genetic condition is detectable.
Positive screening results could result in follow-up invasive diagnostic testing (CVS at 10–13 weeks or amniocentesis at 15+ weeks), if you choose.
Some people simply prefer not to know, and that's a valid choice.
Navigating results can bring ethical and emotional complexity that's hard to prepare for.
Prenatal genetic screening cost: what to expect
Cost is often one of the first questions — and it's a fair one. The good news is that genetic screening is more accessible than ever.
There's generally good insurance coverage, and many labs have a cash-pay option or financing to make these screens accessible.
Myriad Genetics, as one example, reports that most patients pay less than $100 for their tests, and financial assistance programs are available. They also provide cost estimates within days of receiving your sample, so you're not blindsided by a bill later. Without insurance, out-of-pocket costs can range from $100 to $2,000, depending on how comprehensive the panel is.
If you're concerned about cost, call your insurance company for their estimate on NIPT and/or carrier screening before you go to your prenatal visit. Then you can make educated decisions based on your provider's recommendations and your own finances.
What happens after your prenatal genetic testing results
If your results come back low-risk or negative, your pregnancy continues with routine care. That's the outcome for the vast majority of people.
If results come back high-risk or positive, the first step is usually a referral for genetic counseling. A genetic counselor will walk you through exactly what the results mean, what the actual probabilities are, and what your options look like going forward.
Diagnostic testing is invasive and carries a small risk of complications, but it can deliver more definitive answers for many conditions.
If a diagnostic test confirms a condition, you'll have time to make decisions with the support of genetic counselors and maternal-fetal medicine specialists. There's no single "right" path forward, and support is available no matter what you decide.
Who should consider prenatal genetic testing?
Prenatal genetic screening used to be reserved for people considered "high risk," but that's no longer the case. The landscape of prenatal genetics continues to evolve rapidly, with improvements in processing speed and technology. Today, screening is offered to all pregnant people regardless of age or risk factors.
That said, testing may feel especially relevant if you're 35 or older, have a family history of genetic conditions, have had a previous pregnancy affected by a chromosomal change, have abnormal ultrasound findings, or simply want more information to ease your mind. Carrier screening may also be particularly valuable based on ethnic background and family history.
If you're weighing genetic testing options during fertility treatment, many of the same principles apply — knowledge is power, and you get to decide how much of it you want.
The choice is always yours.
The bottom line: you're in the driver's seat
Pregnancy comes with a sometimes overwhelming number of decisions, and genetic testing is one. It's okay to feel uncertain about what's right for you. It's okay to want all the information, and it's equally okay to opt out.
What matters is that you feel supported in whatever you choose. Your healthcare provider, genetic counselors (including resources available through labs like Myriad Genetics), and maternal-fetal medicine specialists are there to guide you — not to push you in any direction.
Most pregnancies result in healthy babies. Screening is one tool among many that can help you feel prepared and informed along the way. Whatever you decide is the right decision for your family.
