Prenatal testing: Quick guide to common tests

Date Updated: 12/06/2022

Prenatal testing is offered in all 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 trisomy 13 and fetal sex	Possible invasive testing, such as chorionic villus sampling or amniocentesis
1st 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; cell-free DNA screening may also be considered
Quad screen
Blood test	15-22 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; cell-free DNA screening may also be considered

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.