When is amniotic fluid tested

Back to Health A to Z. Amniocentesis is a test you may be offered during pregnancy to check if your baby has a genetic or chromosomal condition, such as Down's syndrome, Edwards' syndrome or Patau's syndrome. It involves removing and testing a small sample of cells from amniotic fluid, the fluid that surrounds the unborn baby in the womb uterus. Amniocentesis is not offered to all pregnant women. It's only offered if there's a higher chance your baby could have a genetic condition. It's important to remember that you do not have to have amniocentesis if it's offered.

It's up to you to decide whether you want it. A midwife or doctor will speak to you about what the test involves and let you know what the possible benefits and risks are to help you make a decision. Find out about why amniocentesis is offered and deciding whether to have it. Amniocentesis is usually carried out between the 15th and 20th weeks of pregnancy, but you can have it later if necessary.

It can be performed earlier, but this may increase the risk of complications of amniocentesis and is usually avoided. During the test, a long, thin needle is inserted through your abdominal wall, guided by an ultrasound image. The needle is passed into the amniotic sac that surrounds the foetus and a small sample of amniotic fluid is removed for analysis. The test itself usually takes about 10 minutes, although the whole consultation may take about 30 minutes.

Some women describe experiencing a pain similar to period pain or feeling pressure when the needle is taken out. You may be told to rest on your left side. After the test, rest at home and avoid strenuous activities for at least 24 hours, or as directed by your healthcare provider. Your healthcare provider may give you other instructions after the procedure, depending on your situation. Health Home Treatments, Tests and Therapies.

Amniotic fluid is a clear, pale yellow fluid that: Protects the fetus from injury Protects against infection Allows the baby to move and develop properly Helps control the temperature of the fetus Along with various enzymes, proteins, hormones, and other substances, the amniotic fluid contains cells shed by the fetus. Why might I need an amniocentesis? Some conditions where an amniocentesis may be used for genetic and chromosome testing in the second trimester of pregnancy include: Family history or previous child with a genetic disease or metabolic disorder, such as Down syndrome, cystic fibrosis, or Tay Sachs disease Risk of open neural tube defects, such as spina bifida Maternal age over 35 years by the pregnancy due date Abnormal maternal screening tests Risk of a sex-linked genetic disease Amniocentesis may be used in the third trimester of pregnancy to check for: Fetal lung maturity when there is a potential for premature birth Uterine infection Rh disease Your healthcare provider may have other reasons to recommend an amniocentesis.

What are the risks of an amniocentesis? Certain factors or conditions may interfere with an amniocentesis. These factors include: Pregnancy earlier than 14 weeks The position of the baby, placenta, amount of fluid, or mother's anatomy Women with twins or other multiples will need fluid samples from each amniotic sac to study each baby You may have other risks, depending on your condition. How do I get ready for an amniocentesis? Your healthcare provider will explain the procedure and you can ask questions.

You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if anything is unclear. Generally, there are no special limits on diet or activity before an amniocentesis. Tell your healthcare provider if you are sensitive to or are allergic to any medicines, latex, tape, or anesthesia. Tell your healthcare provider of all medicines prescription and over-the-counter , herbs, vitamins, and supplements that you are taking.

Tell your healthcare provider if you have a history of bleeding disorders or if you are taking any anticoagulant blood-thinning medicines, aspirin, or other medicines that affect blood clotting.

You may be told to stop these medicines before the procedure. Make sure your healthcare provider knows if your blood type is Rh negative. During the amniocentesis, blood cells from the mother and fetus can mix. This can lead to Rh sensitization and breaking down of fetal red blood cells if you are Rh negative and your baby is Rh positive.

You may or may not be asked to empty your bladder right before the procedure. In early pregnancy, a full bladder helps move the uterus into a better position for the procedure. In later pregnancy, the bladder should be empty to lower the risk of puncture with the amniocentesis needle. Follow any other instructions your provider gives you to get ready. Children may feel stomach pain for a range of reasons and may need treatment. Content on this website is provided for information purposes only.

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Summary Read the full fact sheet. On this page. Problems detected by amniocentesis Women who may benefit from amniocentesis The amniocentesis procedure Immediately after amniocentesis Complications of amniocentesis Taking care of yourself at home Long-term outlook after amniocentesis Where to get help Things to remember. Problems detected by amniocentesis Amniocentesis can detect a number of chromosomal and other birth abnormalities in a developing fetus. These include: Down syndrome Neural tube defects, such as spina bifida Genetic disorders — amniotic fluid samples can be DNA tested to identify a range of genetic disorders, such as cystic fibrosis and fragile X syndrome.

Women who may benefit from amniocentesis As a woman grows older, the risk of having a child with Down syndrome begins to increase significantly — from about one in 2, at age 20 years to one in at 40 years. Pregnant women who may be candidates for amniocentesis include: Women over the age of 40 years Victorian women aged 37 years and over are routinely offered this test Women with a family history of chromosomal abnormalities, such as Down syndrome Women who have already had children with chromosomal abnormalities Women known to be carriers of genetic disorders Women with partners who have a family history of a genetic disorder or chromosomal abnormality Women who return an abnormal 'serum screen' blood test or ultrasound examination result.

The amniocentesis procedure Before having amniocentesis, it is usual for the woman and her partner to be counselled on the risks of the procedure. Steps involved in amniocentesis: The woman lies down and the position of the fetus and the placenta are determined by an ultrasound scan.

When the doctor is sure of a safe spot, they swab the woman's belly with antiseptic and inject a local anaesthetic into the skin. Using a long, thin needle, the doctor extracts about 15 to 20ml approximately three teaspoons of amniotic fluid. This takes about 30 seconds. The fetus is checked afterwards to make sure all is well.

Immediately after amniocentesis You may need to wait in the surgery for around 20 minutes before leaving for home. Side effects of the procedure may include: Mild discomfort Slight bruising at the injection site.