When Can You Do a DNA Test During Pregnancy?

Learn when to take a DNA test during pregnancy in 2026. NIPT cell-free DNA screening from week 10—accurate, safe, and US-approved. Compare options here.

You can do a DNA test during pregnancy as early as week 10 with non-invasive prenatal testing (NIPT), also known as cell-free DNA screening. This blood test analyzes fetal DNA circulating in your bloodstream to screen for common chromosomal conditions like Down syndrome (trisomy 21), trisomy 18, and trisomy 13. In the US, NIPT is the most common DNA-based prenatal screening and is typically offered from 10 weeks gestation onward. Unlike diagnostic procedures such as chorionic villus sampling (CVS) or amniocentesis, NIPT carries no risk of miscarriage and is recommended by the American College of Obstetricians and Gynecologists (ACOG) as a first-line screening option for all pregnancies, regardless of maternal age.

Types of DNA-Based Prenatal Tests and Their Timing

Non-Invasive Prenatal Testing (NIPT) – Cell-Free DNA

NIPT is the earliest DNA test you can take. It requires only a maternal blood draw and can be done as soon as 10 weeks into pregnancy. Results are typically available within 7–10 business days. The test measures the relative amount of DNA from chromosomes 21, 18, 13, and the sex chromosomes. It can also determine fetal sex and, in some panels, screen for microdeletions. Fetal fraction—the percentage of cell-free DNA from the placenta—must be at least 4% for accurate results; this is usually achieved by week 10.

Carrier Screening

Carrier screening is a DNA blood test that can be done before pregnancy or at any point during the first trimester. It checks whether you carry genes for inherited conditions such as cystic fibrosis, spinal muscular atrophy (SMA), or fragile X syndrome. Many US providers offer expanded carrier panels that test for over 100 conditions. Timing is flexible, but early testing (before 12 weeks) allows you to discuss results with a genetic counselor and plan further testing if needed.

First-Trimester Screening (Combined Test)

This is not a DNA test in the strict sense but combines a blood test for pregnancy-associated plasma protein A (PAPP-A) and human chorionic gonadotropin (hCG) with a nuchal translucency ultrasound. It is performed between 11 and 13 weeks. While it screens for the same conditions as NIPT, it has a higher false-positive rate. Many US patients now choose NIPT instead of or in addition to first-trimester screening.

Integrated Screening

Integrated screening combines first-trimester blood work and ultrasound with a second-trimester quad screen (alpha-fetoprotein, hCG, estriol, inhibin A). Results are available around 16–18 weeks. Because NIPT provides earlier and more accurate results, integrated screening is used less frequently today.

Diagnostic DNA Tests: CVS and Amniocentesis

Chorionic villus sampling (CVS): Performed between 10–13 weeks. A small sample of placental tissue is taken. It is diagnostic but carries a 1-in-300 to 1-in-500 risk of miscarriage.
Amniocentesis: Performed between 15–20 weeks. A sample of amniotic fluid is analyzed. Miscarriage risk is about 1-in-500 to 1-in-900.

Both are typically offered after a positive NIPT or carrier screening result, or for women over 35.

Comparison of DNA Test Timelines

Test Type	Earliest Timing	Results Window	Risk
NIPT (cell-free DNA)	10 weeks	7–10 days	None
Carrier screening	Any time (pre-conception or early pregnancy)	5–14 days	None
First-trimester screening	11 weeks	1–3 days	None
CVS (diagnostic)	10–13 weeks	7–14 days	~1 in 300–500 miscarriage
Amniocentesis (diagnostic)	15–20 weeks	7–14 days	~1 in 500–900 miscarriage

What About a Prenatal Paternity Test?

Non-invasive prenatal paternity testing is also available from week 8–10 using a maternal blood sample and a cheek swab from the alleged father. This is a separate DNA test and is not part of standard medical screening panels. It is not covered by insurance and costs vary widely.

Why Timing Matters: Fetal Fraction and Accuracy

NIPT accuracy depends on sufficient fetal fraction. Before 10 weeks, fetal fraction may be too low, leading to a "no-call" result. By 10–12 weeks, fetal fraction typically exceeds 4%, giving detection rates above 99% for trisomy 21 and 97% for trisomy 18. A genetic counselor can help interpret borderline results and coordinate follow-up.

2026 US Guidelines and Insurance

Most US insurance plans cover NIPT for women 35 and older, or those with other risk factors. Many now cover it for all pregnancies due to updated ACOG recommendations. Carrier screening is often covered once per lifetime. Always check with your provider—some require prior authorization. If you are unsure which test to choose, a genetic counselor can guide you.

Frequently Asked Questions

Can a DNA test be done before 10 weeks?

NIPT is not recommended before 10 weeks because fetal fraction may be too low for accurate results. Some labs offer it from 9 weeks, but ACOG advises waiting until 10 weeks. Carrier screening can be done anytime, even before pregnancy.

What is the difference between NIPT and carrier screening?

NIPT screens for chromosomal conditions in the baby (e.g., Down syndrome). Carrier screening checks if the mother (or father) carries genes for inherited disorders like cystic fibrosis or SMA. Both are DNA tests but answer different questions.

Is NIPT covered by insurance in 2026?

Most US insurers cover NIPT for women 35+ or with risk factors. Many now cover it for all pregnancies. Carrier screening is usually covered once per lifetime. Check with your plan—some require a doctor's referral.

Understanding when you can do a DNA test during pregnancy helps you make informed decisions about your prenatal care. For a complete picture of your baby's health, consider combining NIPT with carrier screening. You can order a prenatal screening panel online today and receive results quickly, with secure lab processing and confidential support.