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Friday, January 16, 2009


What is amniocentesis and what is amniotic fluid?
The amnion is the sac (membrane) which surrounds the embryo (an embryo is the fetus of 8th
week age) in the uterus. A fluid accumulates within this sac, which is called amniotic
fluid and can be withdrawn through a process called amniocentesis. This can be done after
the fetus growth at the stage of 13th week to analyze the fetus condition. In this process,
after the fluid withdrawal, the fluid will be cultured, and the cells of the fetus in the
fluid are grown, and then analyzed by microscopic process.

What is the importance of amniocentesis in child birth?
Using this method a karyotype or classification of chromosomes are done to analyze the
chromosomes in those cells. The presence of high levels of certain chemicals may indicate
defects if any in the developing spinal cord and spinal column of the fetus.

How is amniocentesis is performed?
Amniocentesis (also referred to as amniotic fluid test or AFT), is a medical procedure used
in prenatal diagnosis of chromosomal abnormalities and fetal infections [1], 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

Before the actual procedure, a local anesthetic is sometimes given to relieve the pain when
inserting the needle used to withdraw the fluid. A needle is usually inserted through the
mother's abdominal wall or at the end of the vagina, and through the wall of the uterus into
the amniotic sac. With assistance from ultrasound, a physician aims towards an area of the
sac that is away from the fetus and extracts a small amount of amniotic fluid for
testing.The puncture heals, and the amniotic sac replenishes the liquid over a day or so.
After the amniotic fluid is extracted, the fetal cells are separated from it using a
centrifuge, and the fetal chromosomes are examined for abnormalities. Various genetic
testing may be performed, but the three most common abnormalities tested for are Down
syndrome, Trisomy 18 and spina bifida. Amniocentesis can be performed as soon as sufficient
amniotic fluid surrounds the fetus to allow a sample to be recovered relatively safely,
usually no earlier than the 14th or 15th week of pregnancy. Often, genetic counseling is
offered in conjunction with amniocentesis.

What is the risk of this procedure?

The amniotic sac may get infected while using the needle to withdraw fluid from it, and if
the puncture made by the needle failed, this also can cause infection or leakage of amniotic
fluid, and may lead to miscarriage in serious conditions. The other possible complications
are preterm labor and delivery, respiratory distress, postural deformities, fetal trauma and
alloimmunisation (rhesus disease).

In the series of learning some important terms under the heading appendices, we will learn
next about streptococcus and staphylococcus..ok

Come on...

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