Friday, March 25, 2011

Amniocentesis: A Prenatal DNA Paternity Testing

Deutsch: Pathomechanismus der Fruchtwasserembo...
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Aside from the traditional blood sample, there are several methods using various sampling now available in profiling DNA for paternity identification.

One of these advanced systems is called amniocentesis. It is also known as amniotic fluid test or AFT. Originally, amniocentesis is a prenatal procedure to diagnose the chromosomal abnormalities and fetal infections.


The amniocentesis is performed in the second trimester or during the 14th to 20th weeks of pregnancy. In this procedure, the OB-GYN uses ultrasound to guide a thin needle into the uterus passing through the abdominal wall then finally into the amnion or amniotic sac. Before the procedure starts, local anesthetic is provided to the pregnant woman in order to relieve the pain felt when the insertion of needle happens.

The needle draws out a sufficient amount of amniotic fluid. This is about 20ml. This fluid is extracted from the amnion sac that surrounds the fetus. The fluid contains fetal tissues. After the extraction of amniotic fluid, the fetal cells shall be separated from the sample. It will be grown in a culture medium, fixed, and then stained. After the procedure, the puncture heals and the amniotic sac replenishes the liquid within 24 to 48 hours.

This procedure is usually performed in the hospital. Then it will be collected by laboratories for testing. Generally, results are available within three to five working days.

Aside from paternity DNA testing and as mentioned above, this procedure is used to examine the child for possible abnormalities such as anencephaly, Down syndrome, Edward syndrome, and Tunner syndrome, Trisomy 13 and 18, inherited metabolic disorders, infection, Rh incompatibility, and spina bifida.

Amniocentesis poses risks to pregnancy. Undergoing this procedure will have a small chance of serious complications such as harming the baby and miscarriage. Way back in the 1970s, studies showed that amniocentesis causes miscarriage at a rate of 1 in 200, or barely half of one percent. Three decades after, studies found out that there is lesser amniocentesis-related miscarriage – only about 1 in 1,600 cases or about .6 percent.

This procedure might also cause injury to the child’s limbs. Other adverse effects may also be cramping, leaking of amniotic fluid, and vaginal bleeding. Yet, records show that about six percent of pregnant women consider undergoing the amniocentesis procedure. In addition, about 7% of women who undergo this text have not felt any discomfort.

Other possible complications may include infection of the amniotic sac from the needle. In addition, there is a possibility that the puncture will not heal properly that can result to leakage or infection of the amniotic sac. It may also cause preterm labor and delivery, postural deformities, respiratory distress, and fetal trauma.

Meanwhile, experts are also amniotic fluid as possible source of several kinds of stem cells. One of the possible benefits of amniotic stem cells is that it avoids ethical concerns among pro-life advocates. Today, there is one active amniotic stem cell in the United States.

It should be noted that pregnant women who wants to undergo such procedure for paternity DNA testing would need a doctor’s consent.