Amniocentesis

Procedure used in prenatal diagnosis to obtain amniotic fluid which can be used for genetic and other diagnostic tests. Informally called

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Transabdominal aspiration of fluid from the amniotic sac. [amnio- + G. kentesis, puncture]

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am·nio·cen·te·sis .am-nē-ō-(.)sen-'tē-səs n, pl -te·ses -.sēz the surgical insertion of a hollow needle through the abdominal wall and into the uterus of a pregnant female to obtain amniotic fluid esp. to examine the fetal chromosomes for an abnormality and for the determination of sex

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n.

withdrawal of a sample of the fluid (amniotic fluid) surrounding an embryo in the uterus by piercing the amniotic sac through the abdominal wall. As the amniotic fluid contains cells from the embryo (mostly shed from the skin), cell cultures enable chromosome patterns to be studied so that prenatal diagnosis of chromosomal abnormalities (such as Down's syndrome) can be made. Metabolic errors and other diseases, such as spina bifida, can also be diagnosed prenatally from the biochemistry of the cells or that of the fluid (see alpha-fetoprotein). Although the risks of amniocentesis, in skilled hands, are extremely low, there is no point in undertaking it unless the parents agree to a termination of the pregnancy if a serious abnormality is discovered.

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am·nio·cen·te·sis (am″ne-o-sen-teґsis) percutaneous transabdominal puncture of the uterus to obtain amniotic fluid.

Amniocentesis.