(MayoClinic.com) 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|
|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.
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