Prenatal Screening Tests: What They Check and How to Order

What Is Prenatal Screening?

Prenatal screening is a group of tests done before or during pregnancy to assess the chance of certain inherited or chromosome conditions. Screening does not give a yes or no diagnosis. Instead, it estimates risk and helps people decide whether to pursue diagnostic testing.

There are two broad categories. Carrier screening tests the parents, usually before or early in pregnancy, to see whether they carry a gene change for a recessive condition. Fetal screening tests the pregnancy to assess the chance of chromosome conditions such as trisomy 21, 18, or 13.

Screening is optional and personal. A clinician or genetic counselor can explain what each test can and cannot tell you so the decision fits your situation.

Timing matters because some screens are only accurate during certain weeks. Carrier screening, by contrast, can be done before pregnancy or at any point, and doing it early gives more time to plan.

Types of Prenatal Screening Tests

Common options include:

• Carrier screening — a blood or saliva test that checks for gene changes linked to inherited conditions
• Cell-free DNA screening — a maternal blood test that analyzes placental DNA to assess chromosome risk
• First-trimester combined screen — ultrasound plus blood markers
• Second-trimester maternal serum screen — blood markers that estimate risk

Your clinician can help decide which tests fit your history and preferences, and some are best done at specific weeks of pregnancy.

Each option has strengths and limits. Carrier screening looks at the parents, while fetal screening looks at the pregnancy. Some people choose one, some choose several, and some decline screening altogether.

Carrier Screening: SMA, Fragile X, and Cystic Fibrosis

Carrier screening looks for gene changes that a person can carry without having symptoms. If both parents carry a change in the same gene, each pregnancy has a chance of being affected. Three commonly offered examples are:

Frequencies vary by ancestry and laboratory, so a result is always interpreted against the range on your report. Some panels screen for many conditions at once.

Expanded panels can check dozens or hundreds of conditions at once, which is why results sometimes include findings for conditions a person had not considered. Genetic counseling helps put those findings in context.

What the Results Mean

A negative carrier screen means no tested gene change was found. This greatly reduces, but does not fully eliminate, the chance of being a carrier, because some changes may not be detected. A positive carrier screen means a change was found; it does not mean you have the condition, but it may prompt testing of your partner. For fetal screening, a low-risk result means the chance is low, while a higher-risk result means diagnostic testing may be offered.

An unclear or inconclusive result is also possible, and it usually means more testing or a referral. A result should never be read in isolation from family history and clinical advice.

Screening Versus Diagnostic Testing

Screening estimates risk; it does not confirm a diagnosis. If a screen is positive or higher-risk, a clinician may offer diagnostic testing such as chorionic villus sampling or amniocentesis, which collect fetal cells for analysis. Those procedures carry a small risk of pregnancy loss, so the decision is personal and best made with a clinician and, often, a genetic counselor. Understanding the difference helps people make informed choices about next steps.

How to Order Prenatal Screening

Carrier screening can be ordered directly through direct-access lab testing, often with a blood or saliva sample collected at a local site. Fetal screening is typically arranged through prenatal care, because timing and follow-up matter. Results are posted to a secure account or shared through your care team. Genetic counseling is recommended whenever a result is positive or unclear.

Before ordering, it helps to know whether your clinician wants a targeted test or a broad panel, since that changes both the cost and the counseling needs.

How Much Does Prenatal Screening Cost?

Direct-access carrier screening commonly costs about $100 to $500, depending on how many genes are included. Expanded panels cost more than single-gene tests. Fetal screening such as cell-free DNA testing commonly costs about $200 to $800 when paid directly. Insurance is not required, and prices are usually shown up front.