If you are close to or on the other side of 35 years old and pregnant, you have probably been offered the option of doing an amniocentesis. An amniocentesis is a screening procedure that extracts amniotic fluid from the uterus and examines it for genetic disorders or chromosomal abnormalities such as Down syndrome. The test however will not determine whether or not the fetus has structural defects such as heart malformations or cleft palate.

When is it Done?

Amniocentesis is usually scheduled between weeks 15 and 20, but more often than not done around weeks 16-18 – or at the beginning of the second trimester. Some studies have shown a small risk of the development of clubfeet if the procedure is done before 16 weeks, which is why it is most often not scheduled before this point in pregnancy.

How is it Done?

The procedure is started with a pregnant woman lying on her back with her belly exposed. A doctor would begin by doing an ultrasound to determine where the baby and the placenta are.  This would help determine where he/she could safely insert the needle.

The needle is inserted into the abdomen, then uterus of the pregnant woman and aims to withdraw a small sample of the amniotic fluid that wraps the fetus. About an ounce of fluid is removed and sent for testing as it contains cells that carry genetic information from the fetus.

During the amnio some women may feel pressure or cramping. Some women may not feel any discomfort. 

Are their Risks?

Yes. With Amniocentesis there is an approximate 1% risk that the pregnancy will be terminated. This is either due to a loss of too much amniotic fluid or due to an infection that develops as a result of the procedure.

In order to minimize the risk of miscarriage it is wise to ask about the experience level of the doctor that is scheduled to perform the procedure. Ensure you are working with a doctor with a great track record of healthy and safe amniocenteses.

Who is it for?

Amniocentesis is recommended for women over 35 years of age as there is a greater likelihood of birth defects and chromosomal abnormalities after this point. It is also recommended for women who have had a child with birth defects or for couples with a family history of abnormalities. 

Is it for Everyone?

Amniocentesis is not for everyone. Many women choose not to undergo the procedure as it does carry some risks with it. Some women are not comfortable with any risks to their pregnancy and choose to use other screening procedures that are less accurate, but pose fewer potential problems.

Amniocentesis may also not be a good option for women or couples whose decision to continue with the pregnancy would not be altered by the results from the procedure. For a woman who would not terminate a pregnancy under any circumstances, an amniocentesis may not be necessary. 

After the Procedure

After an amniocentesis women are instructed to rest for the remainder of the day and often even for the next day. It is recommended that they avoid lifting heavy objects, doing hard labor or having sex in the days following. 

If you develop a fever, start bleeding or begin losing fluid from your vagina call your health care provider immediately. 

Genetic Counseling

Most couples are encouraged to undergo genetic counseling such that all their questions about risks versus benefits are answered properly before they embark on any screening procedures.  Ask your doctor or health care provider about this service. 

Lilian Presti