What Does an Amniocentesis Test For? Birth Terminology Explained

There is so many terms thrown around when you become pregnant. In this "Terminology Explained" series, we help make understanding easier.

Today's term is amniocentesis.

What is Amniocentesis? 

Official Definition: An amniocentesis is an optional prenatal test procedure, performed prenatally (during pregnancy), that can provide information about your baby's health, including diagnosing birth defects. 

An amniocentesis removes a small amount of amniotic fluid from around the baby in the amniotic sac, while still in the uterus, and is performed after your skin is first numbed, then a long, thin needle is inserted in through the abdomen using guidance from ultrasound imaging. The procedure, from start to finish, takes around 45 minutes. 

When you will hear/see the term used? An amniocentesis is an invasive and optional prenatal test and is only recommended for specific reasons. An amniocentesis may be recommended for:

• Neural tube defects
• Chromosome abnormalities
• Genetic disorders
• Fetal infection
• To determine lung development/maturity for birth
• Following an abnormal triple test result
• To treat polyhydramnios (too much amniotic fluid)
• DNA paternity testing

Because an amniocentesis is optional and carries risks, the decision to choose amniocentesis is up to the parents who must weigh the risks and benefits. 

Why is it important/beneficial? Knowledge gained from amniocentesis results can benefit a baby's health in many ways, including performing or planning for critical interventions/treatment that may be needed based on the diagnoses. Typically, amniocentesis is not recommended unless the results could have a significant impact on your baby's health. Because every person's circumstances are unique in a pregnancy, the benefits should be weighed carefully against the potential risks of an amniocentesis test. Risks include:

• Miscarriage (less than 1 in 200 women)
• Uterine infection (rare)
• Cramping, spotting or leaking amniotic fluid 
• Passing infection to your baby (Hep C, HIV, toxoplasmosis)
• Rh problems 
• Injury to the baby from the needle (serious injury is very rare)

For more information about prenatal tests and having a healthy pregnancy, it helps to take a quality childbirth class series, like the classes taught by Lamaze educators. Find one that's right for you!