Prenatal testing: Quick guide to common tests

Prenatal screening tests can provide information about your baby's health before he or she is born. Consider the timing and what prenatal testing can reveal.

By Mayo Clinic Staff

Prenatal testing is offered in most pregnancies. Here's an overview of common prenatal screening tests:

What it is When it's done What the results might tell you Follow-up
Cell-free DNA (cfDNA) screening
Blood test As early as week 10 Risk of Down syndrome (trisomy 21), trisomy 18, and fetal sex Possible invasive testing, such as chorionic villus sampling or amniocentesis
First trimester screening
Blood test and ultrasound 11-14 weeks Risk of Down syndrome (trisomy 21) and trisomy 18 Possible invasive testing, such as chorionic villus sampling or amniocentesis
Quad screen
Blood test 15-20 weeks Risk of Down syndrome (trisomy 21), trisomy 18 and open neural tube defects, such as spina bifida Possible targeted ultrasound, or invasive testing such as chorionic villus sampling or amniocentesis

Some health care providers choose to combine the results of first trimester screening with the quad screen — although you won't learn the final results of this sequential testing until both tests are completed and analyzed.

In addition, fetal ultrasound often plays an important role in prenatal care and screening. Early in pregnancy, ultrasound can be used to confirm and date a pregnancy. Later, ultrasound can be used to detect certain birth defects and fetal anomalies, including neural tube defects.

Blood tests and ultrasounds pose limited risks for you and your baby. If the results of a blood test or ultrasound are positive or worrisome, your health care provider might recommend a more invasive diagnostic test — such as chorionic villus sampling or amniocentesis. These tests can be used to diagnose conditions, but they carry a slight risk of pregnancy loss.

If you're concerned about prenatal testing or wonder whether you need specific screening or diagnostic tests, discuss the risks and benefits with your health care provider.

Oct. 08, 2015 See more In-depth