Amniocentesis is a diagnostic test that is often recommended for women who are pregnant. It is usually requested when there is an abnormal triple test result for some reason. For parents where there may be genetic concerns or inherited conditions that may be present, amniocentesis can help to determine if a child may have genetic disorders developing while in the womb. The procedure itself generally takes about 45 minutes and requires the collection of amniotic fluid.
Facts About Amniocentesis
1. Amniocentesis can detect chromosome and genetic abnormalities with 98-99% accuracy. Some research puts the accuracy rate at 99.4%.
2. More than 200,000 tests are performed every year in the United States.
3. The risk of miscarriage because of an amniocentesis test is 1 in 200 to 1 in 400. 4. Some research puts those risks at 1 in 1,600. The most common causes of miscarriage are because of an infection, induced labor, or breaking the water.
5. The results of the amniocentesis are generally available within 2-3 weeks. Rapid test are ready in 72 hours, but only look for Down’s Syndrome, Edward’s Syndrome, and Patau’s Syndrome.
6. Spontaneous abortions occur in fewer than 1% of women who have this procedure done.
7. Rh Sensitization can occur rarely, which happens a baby’s blood enters the mother’s bloodstream. If the moth is Rh negative, then her body may form antibodies that will attack the red blood cells of the baby’s blood.
There is no cure for a majority of the chromosomal conditions that amniocentesis can find.
8. 1 or 2 women out of every 100 women who have an amniocentesis experience bruising.
9. In less than 1 in 1000 tests (0.1%), a result cannot be obtained from the sample and a repeat test is required.
10. The amniocentesis will identify the sex of the baby. Parents may choose whether or not they wish to be told.
11. Very small chromosome abnormalities cannot be excluded from an amniocentesis test, even if the test results come back negative.
12. An estimated 92% of all women who receive a prenatal diagnosis of Down syndrome choose to terminate their pregnancies.
13. About 400,000 Americans have Down syndrome, which is the most common genetic condition in the United States.
14. In the absence of prenatal testing, the United States would have experienced a 34% increase in the number of Down births between 1989 and 2005.
15. Because of tests like amniocentesis, a 49% swing in the expected birth rates and observed birth rates have occurred for Down syndrome.
Amniocentesis is usually performed between the 14th and 20th weeks of gestation. In some clinics for high risk parents, the test may be performed as early as the 11th week. Sometimes amniocentesis is requested during the third trimester, however, to determine if a uterine infection may be present, if there is fetal anemia when a child has Rh disease, and if a blood transfusion maybe necessary. It can also be done to determine lung maturity.
Why Is There So Much Fear Around Amniocentesis?
The problem that mothers and families have with the results of an amniocentesis test is that there are not many supports in place to help someone make an empowered choice. Many couples are left out on an island and forced into a rapid decision when a positive test result occurs. Many parents are older when they receive these results as well, which means they may not know if they have the strength to be a parent to a child with a genetic or chromosomal disorder. Without support, women choose to end their pregnancy rather than risk future harm.
For the 8% of women who choose to have their children born after a positive amniocentesis test, they say that having resources brought to them and the chance to experience what life is like by meeting families who have gone through the same situation has helped them make a more informed choice. There may be severe challenges, but the supports come through and help mothers, couples, and families make it through the difficult times.
Amniocentesis for many may be a slippery slope. Right now we’re testing for genetics and chromosomes to determine future health. What if we as a society decide that certain physical characteristics aren’t wanted? The amount of Down syndrome births has dropped dramatically because of this test. There’s no telling what the birth rates might be if future tests can determine specific characteristics that aren’t wanted as well.