What is an amniocentesis pregnancy test?
When undergoing an amniocentesis test a little sample of amniotic fluid that is surrounding the fetus is extracted and examined, with the intent to diagnose or rule out the possibility of birth defects and other complications. An amniocentesis pregnancy test is usually carried out around the 15-18 week mark.
The Amniocentesis test is a very common prenatal test used to diagnose chromosomal and genetic birth defects which may lead to Down Syndrome or other disease. Another test that is performed during pregnancy is known as chorionic villus sampling (CVS), this test can also be performed to diagnose most, but not all, of the same birth defects as an amniocentesis test.
Chorionic villus sampling is usually performed earlier than an amniocentesis pregnancy test, this is around 10-15 weeks. Like many tests there are some downsides associated with a CVS test, and possibly the main being a high risk of miscarriage.
Who needs an Amniocentesis Test?
Amniocentesis is not offered to all women who are pregnant because it does carry a small risk of miscarriage and so it is generally offered to pregnant women who may be showing signs that their baby may have some chromosomal or genetic birth defects, or to those who may be at a higher risk of these sorts of complications.
Reasons for needing this type of test
Age – If you are considering pregnancy and will be 35 or older at the time of your scheduled delivery, your healthcare provider may offer you an amniocentesis test. The reason you may be recommended to take the test is because there may be a high risk of your baby developing Down Syndrome and chromosomal disorders in when women who are pregnant over 35.
A Previous Pregnancy with a birth defect – If you had a prior child born with birth defects or chromosomal disorders your doctor may recommend this test. If your family has a history of birth defects or other development diseases, the test may also be offered.
Suggestive screening test results – If you are showing signs of an chromosomal disorder development issues, this test may be suggested.
How is this type of test performed?
This test is performed by inserting a thin, hollow needle into the uterus and extracting some of the amniotic fluid that surrounds the baby.
The pregnant woman then lies flat on her back on a table. The belly is then cleansed thoroughly with an iodine solution. An ultrasoundis then used to help guide the doctor as the needle is inserted through the abdomen into the uterus and into the amniotic sac. About 30ml which equals about two tablespoons of amniotic fluid is then removed.
This type os test usually only takes about 2 minutes. After some fluid is removed the doctor will then monitor the fetal heartbeat for any signs of possible distress.
This procedure is not painful, although some women have reported experiencing some cramping when the needle is entering the uterus. Some women have also reported some spotting and amniotic fluid leaking after the amniocentesis. Your health care provider will probably recommend avoiding any type of physical activity for a few hours once the procedure is complete.
Test results usually take about 3 weeks for complete analysis of the amniotic fluid.
Is Amniocentesis a safe test?
Amniocentesis does have a slight risk of miscarriage, however the rate of miscarriage is 1 in 400 or less than 1% according to some sources. It also leaves a chance of uterine infection, but the chances of this are even less than a miscarriage, with the chances of 1 in 1000. It’s best to talk to your OBGYN about this procedure to give you a complete understanding.