amniocentesis

(noun)

A procedure for obtaining amniotic fluid from a pregnant female by inserting a hollow needle through the abdominal wall and into the amniotic sac. It is used to diagnose possible genetic defects and/or obstetric complications.

Related Terms

Examples of amniocentesis in the following topics:

  • Prenatal Diagnostic Tests

    • ., amniocentesis (that can be done from about 14 weeks gestation up to about 20 weeks), and chorionic villus sampling (that can be done earlier: between 9.5 and 12.5 weeks gestation).
    • Since chorionic villus sampling is performed earlier in the pregnancy than amniocentesis, typically during the first trimester, it can reasonably be expected that there will be a higher rate of miscarriage after chorionic villus sampling than after amniocentesis.
    • Because of the risk of miscarriage and fetal damage associated with amniocentesis and chorionic villus sampling procedures, many women prefer to first undergo screening so they can find out if the fetus' risk of birth defects is high enough to justify the risks of invasive testing.

  • Down Syndrome

    • Genetic counseling along with genetic testing, such as amniocentesis, chorionic villus sampling (CVS), or percutaneous umbilical cord blood sampling can be offered to families who may have an increased chance of having a child with Down syndrome, or where normal prenatal exams indicate possible problems.
    • Confirmation of a positive screen is normally accomplished with amniocentesis or CVS.
    • Amniocentesis is an invasive procedure and involves taking amniotic fluid from the amniotic sac and identifying fetal cells.

  • The TORCH Panel of Tests

    • Hepatitis B is also sometimes included among "other infections," but Hepatitis B is a large virus and does not cross the placenta, hence it cannot infect the fetus unless there have been breaks in the maternal-fetal barrier, such as can occur due to bleeding during childbirth or during amniocentesis.