During pregnancy, amniotic fluid allows our fetus to grow, move and develop. It is a clear, yellowish liquid substance contained in the amniotic sac. Live fetal cells and other substances are also part of this liquid that provides valuable information about our baby’s health before birth.
What is Amniocentesis and how it’s performed?
Amniocentesis is a test in which we can take a sample of the amniotic fluid and send it to a laboratory. The sample, which is less than one ounce, is removed from the sac surrounding your baby with a fine needle through the abdomen under ultrasound guidance. The health care practitioner can see the position of your baby on the screen and by inserting the needle; a sample is removed without causing any injuries to the child. Various tests can be performed with a sample of amniotic fluid. It depends on the genetic risk and indication for this test.
Indications for Amniocentesis
This is performed to search for certain types of birth defects. Because it presents a small risk for the mother and her baby, this test is generally offered to women who are at higher risk of genetic diseases and:
- women with family history of birth defects
- women who previously had a child with birth defect
- women older than 35
- women who had suspicious findings on their ultrasound
You cannot detect all birth defects through this test; it is done to detect certain conditions if the parents are carrying genetic risk for:
- Down syndrome
- Cystic fibrosis
- Duchene muscular dystrophy
- Sickle cell anemia
The benefit of doing this test is important, because we can detect certain neural tube defects. Neural tube defect is a condition where the baby’s brain and spinal column do not develop properly (spina bifida and anencephaly). Amniocentesis can be done if we want to determine maturation of the baby’s lungs or if we want to evaluate the amniotic fluid for infection. An early detection of certain diseases can help our baby to receive proper therapy.
An ultrasound is performed during this procedure to detect other birth defects that amniocentesis cannot detect such as cleft palate, club foot and heart defects. For those women who want to be certain about the baby’s sex, amniocentesis is the most accurate way to determine the baby’s gender before birth.
When is amniocentesis performed?
Women who are recommended for this test should schedule this procedure between their 15th and 18th week of pregnancy. During this period your baby has not gained too much weight and there is enough fluid around the baby to reduce the risk of complications including miscarriage.
Any failed attempts?
Amniocentesis is 99.4% successful; however, it may be occasionally unsuccessful due to technical problems. These technical problems may due to the inability to collect enough amount of amniotic fluid or inability of the collected cells to develop when cultured.
Are there any risks?
There are risks from this procedure. The risk that this could cause miscarriage is extremely low and the latest studies show that it is less than 1% or approximately 1 in 200 to 1 in 400. There are other potential complications such as preterm labor, injury to the baby or mother during procedure, but these are extremely rare. Duration of the procedure is less than 2 hours, and after the procedure you can go home and rest. It is important not to lift heavy objects after the procedure is done or you may increase the risk of early contractions. You can read about more of this information in this article.