Dictionary Meaning and Definition on 'Amniocentesis'
n : (pregnancy) extraction by centesis of amniotic fluid from a
pregnant woman (after the 15th week of pregnancy) to aid
in the diagnosis of fetal abnormalities [syn: amnio]
[also: amniocenteses (pl)]
Wikipedia Meaning and Definition on 'Amniocentesis'
Amniocentesis (also referred to as amniotic fluid test or AFT), is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is extracted from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities.
Before the start of the procedure, a local anesthetic can be given to the mother in order to relieve the pain felt during the insertion of the needle used to withdraw the fluid. After the local is in effect, a needle is usually inserted through the mother's abdominal wall, then through the wall of the uterus, and finally into the amniotic sac. With the aid of ultrasound-guidance, a physician punctures the sac in an area away from the fetus and extracts approximately 20 ml of amniotic fluid. After the amniotic fluid is extracted, the fetal cells are separated from the sample. The cells are grown in a culture medium, then fixed and stained. Under a microscope the chromosomes are examined for abnormalities. The most common abnormalities detected are Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Turner syndrome (monosomy X). In regard to the fetus, the puncture heals and the amniotic sac replenishes the liquid over the next 24–48 hours.[See more about Amniocentesis at Dictionary 3.0 Encyclopedia]