What is amniocentesis?

Amniocentesis is a procedure whereby a sample of the fluid removed from the amniotic sac for analysis. 
The amniotic sac in the uterine cavity. The amniotic sac is the fluid structure inside the pregnant uterus within which the child lives. Fetal cells, proteins, and fetal urine freely move within the pocket.

During amniocentesis, fluid is removed by placing a long needle through the abdominal wall into the amniotic sac. 
Sometimes the woman's skin is injected first with a local anesthetic, but it is usually not necessary. The amniocentesis needle is usually guided into the bag with the help of ultrasound imaging either before or during the procedure performed. Once the needle in the bottle is a spray used to the bright orange-stained amniotic fluid, resembling urine extract. The volume of fluid withdrawn depends on the age of the fetus and the reason for the test.

The fluid can be sent for evaluation of fetal lung maturity, genetic evaluation, evidence of spina bifida (a birth defect in spinal cord development) or other neural tube defects, the presence of infection, or chromosomal analysis. 
Chromosomes are structures of all the genetic information in our cells. The amniotic fluid contains many free-floating fetal cells that can be used in a laboratory grown. When these cells multiply and reach a certain number, they withdrew and chromosomes analyzed. It takes about two weeks chromosome analysis carried out. The liquid contains proteins, minerals and other substances that can be tested, and these studies 1 to 7 days to act. Data obtained from amniotic fluid can help women to make informed decisions about their pregnancies and babies.

For most patients, amniocentesis is a relatively quick and easy process. 
Some women experience some uterine cramping or a feeling of faintness.

Who is a candidate for amniocentesis?

Women over the age of 35 have a greater chance of carrying a baby with chromosomal abnormalities. 
Thus, the current recommendation that women age 35 years or older at the time of delivery considering an amniocentesis for fetal chromosome test. Chromosomal abnormalities in the fetus can lead to mental retardation or other birth defects as seen with Down's syndrome. The possibility of a baby with a chromosomal defect increases with the age of the mother.

At age 35 the odds are about 1 in 178.

At age 40, the rate increased to 1 in 63.

At age 48, the ratio is 1 in 8.

For women younger than 35, the risk of complications as a result of an amniocentesis outweigh the possibility that the baby has a chromosomal abnormality (see below, "Is Amniocentesis Safe").

After 35, the chance of carrying a baby with a chromosomal abnormality is more common than the experience of the complications associated with this process.
If a family history of chromosomal problems or history of previous births that a chromosomal problem is found, amniocentesis may be recommended. 
However, the exact benefits of amniocentesis in this situation is uncertain. Many chromosomal abnormalities can not again in subsequent pregnancies, and genetic counseling can help a woman decide if amniocentesis would be of value in such situations.

What does amniocentesis show?

Amniocentesis is very accurate in the detection of chromosomal abnormalities and sex of the fetus. 
Sometimes the fetal cells harvested amniocentesis does not grow in culture and no chromosome data obtained. In addition, the doctor is sometimes unable to withdraw fluid from the uterus during amniocentesis due to a variety of technical reasons. In both cases, the process is repeated.

Amniocentesis test for lung maturity may help the physician make decisions regarding the timing of delivery for women in preterm labor, or people with diabetes or other medical conditions requiring delivery. 
Lung maturity test is not perfect. In exceptional cases, a baby born with apparently mature lungs, but still experienced breathing problems.

AFP (alpha feto. Protein) blood test is available and can be used to screen for neural tube defects like spina bifida and Down's syndrome. 
An elevated blood level of AFP may indicate the possibility that the fetus has a defect in the brain and spinal cord development. A low level of AFP may indicate the potential for Down's syndrome. When abnormal levels of AFP are found, further evaluation with ultrasound and amniocentesis done to check for birth defects and chromosomal abnormalities.

Amniocentesis can also help to determine whether specific genetic problems in the fetus. 
Testing for Tay-Sachs disease cystic fibrosis, sickle cell anemia and other hereditary diseases can be performed on samples of amniotic fluid. The control of the cells for a specific gene can now be done on the fetal cell cultures. It is also possible to look for a specific protein in the amniotic fluid may indicate a genetic defect. Testing for genetic (inherited) disease is not often performed, but it is available.

Another common reason for performing amniocentesis to determine if the fetal lungs are mature enough so the baby can safely be delivered before the due date.If the fetal lungs are not mature, an attempt to aid premature labor with medication to stop. 
If the adult lung tissue, it may be safe for the premature baby to be born.This test can also help in the time of delivery when the due date is uncertain.

Sometimes a pregnant woman has a fever without an obvious site of infection. 
In these cases, an amniocentesis is performed to determine the cause of maternal fever is an intra-infection, when the source of infection is unclear.

The general possibility of birth defects in a pregnancy is about 3%. 
For defects such as cleft lip, hernia, and extra fingers or toes, there are no prenatal tests and amniocentesis will not benefit. Ultrasound is the only useful test in detecting these defects in the fetus.

When should amniocentesis be done?

For genetic testing, chromosome analysis and evaluation of an abnormal AFP test, amniocentesis is usually between the 15th and 20th weeks of pregnancy.There is a higher rate of miscarriage associated with amniocentesis earlier than the 15th week running. 
There is no restriction on how late in pregnancy, amniocentesis can be performed.

If amniocentesis is performed for fetal lung maturity to determine, it is often done anywhere between the 32nd and 36th week of pregnancy. 
In women with diabetes, lung maturity test can be done as late as the 39th week, because poorly controlled diabetes can delay fetal lung maturity.

Amniocentesis is safe?

Overall, amniocentesis is a safe procedure with a risk of fetal loss at generally less than 1%. 
According to the American College of Obstetricians and Gynecologists Practice Bulletin, there is a procedural fetal loss rate ranging from 1/300 to 1/500 procedures.

Since there is the slight possibility of pregnancy loss from the procedure, amniocentesis should be performed only when clearly indicated and its benefits are determined for any associated risks outweigh. 
Many parents ask for the procedure to "assure" them that everything is perfect. It should be emphasized that an amniocentesis with normal results do not guarantee that the baby a birth or a genetic defect. Many birth defects can not be detected by amniocentesis.Besides fetal loss, other risks associated with amniocentesis bleeding, cramps and leakage of fluid from the vagina. These problems occur in about 1% of women who undergo the procedure, and generally resolve on their own. If these symptoms arise from the process, women are often advised to quit work and stay on bed rest until the symptoms cease. Subsequent activity will be prohibited by the doctor. Sometimes the fetus put the needle in the test, but it is usually harmless.

Amniocentesis is a relatively safe and painless procedure that can provide useful information. 
The procedure can be offered to selected women after reviewing the risks and benefits involved.

The amniocentesis At a Glance

Amniocentesis can be performed for chromosome analysis or the detection ofgenetic disorders and conditions in the fetus.

Pregnant women over the age of 35 are candidates for amniocentesischromosomal abnormalities to detect the fetus.

Amniocentesis can also be used to mature the lungs of the fetus or the cause of an unknown fever in the mother to determine.

For genetic testing, chromosome analysis, and evaluation of an abnormal alphafeto protein test, amniocentesis is usually between the 15th and 20th weeks ofpregnancy.

The risk of fetal loss of the amniocentesis procedure is less than 1%

Proposed: Amniocentesis Main section

During an amniocentesis, a sample of amniotic fluid is taken to screen for certainbirth defects (Down's syndrome, neural tube defects, spina bifida, cystic fibrosis),lung maturity of the fetus, infection, or chromosomal analysis. Amniocentesis is recommended for women who give birth after the age of 35