amniocentesis
Pronunciation: am-nee-oh-sen-TEE-sis
Diagnostic procedure involving needle insertion through the maternal abdomen into the amniotic sac to obtain fetal cells for genetic testing.
Full Definition
Amniocentesis is an invasive prenatal diagnostic procedure typically performed between 15-20 weeks of pregnancy. A thin needle is inserted through the mother's abdomen and uterine wall into the amniotic cavity to withdraw a small amount of amniotic fluid containing fetal cells. This fluid is analyzed for chromosomal abnormalities, genetic disorders, and neural tube defects. The procedure carries a small risk of miscarriage and is usually offered to women at increased risk for genetic abnormalities based on maternal age, family history, or abnormal screening results.
Usage
Usage note: Distinguish from CVS (chorionic villus sampling) which is performed earlier in pregnancy.
In Context
- "Amniocentesis was offered due to advanced maternal age and elevated AFP levels." — Genetic counseling documentation
- "The amniocentesis results revealed trisomy 21, confirming Down syndrome." — Laboratory report