Prenatal testing: Quick guide to common tests

 Prenatal testing can provide information about your baby's health before he or she is born. Consider the timing and what the tests 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
Noninvasive prenatal testing
Blood test	As early as week 10 in high-risk groups	Risk of Down syndrome (trisomy 21) and certain other chromosomal conditions	Possible chorionic villus sampling or amniocentesis
First trimester screening
Blood test and ultrasound	11-14 weeks	Risk of Down syndrome (trisomy 21) or Edwards syndrome (trisomy 18)	Possible chorionic villus sampling or amniocentesis
Quad screen
Blood test	15-20 weeks	Risk of Down syndrome or spina bifida	Possible targeted ultrasound, 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. Early in pregnancy, ultrasound can be used to confirm and date a pregnancy. Later, ultrasound can be used for many things — such as checking a baby's well-being, monitoring a baby's growth and development, and detecting certain birth defects.

Blood tests and ultrasounds pose no risks for you or 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 provide more detailed or definitive information, 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.