Amniocentesis (amniotic fluid test) Test
Amniocentesis is a test done during pregnancy to diagnose certain genetic disorders, birth defects, and other conditions in your unborn baby. A sample of amniotic fluid is taken from your abdomen, usually between weeks 15 and 20 of pregnancy. The results are almost always accurate.
What this test measures
Amniocentesis measures the levels of certain substances or analyzes cells in the amniotic fluid to diagnose genetic and chromosomal disorders (like Down syndrome, cystic fibrosis, sickle cell disease, Tay-Sachs disease), neural tube defects (like spina bifida and anencephaly), and can also check your baby's lung development or diagnose an infection.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Frequently asked questions
What is amniocentesis?
Amniocentesis is a test done during pregnancy where a sample of amniotic fluid is taken from your abdomen to diagnose certain health problems in your unborn baby.
When is amniocentesis usually done?
The test is usually done between weeks 15 and 20 of pregnancy.
What conditions can amniocentesis detect?
It can detect genetic and chromosomal disorders like Down syndrome, cystic fibrosis, sickle cell disease, Tay-Sachs disease, and neural tube defects like spina bifida and anencephaly.
What does a normal result mean?
A normal result means it is very unlikely that your baby has the disorder that was tested, but it does not guarantee your baby will not have any health problems.
What does an abnormal result mean?
An abnormal result means your baby very likely has the disorder that was tested. Your provider will explain the results and may order more tests.
Related lab tests
Sources
- MedlinePlus: Amniocentesis (amniotic fluid test) — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.