What Does Prenatal Diagnosis Involve?

All moms want their children to have the best medical care possible, even in the womb. Today, we'll tell you about prenatal diagnosis.

Reviewed and approved by the pediatrician Marcela Alejandra Caffulli.

Written by Marcela Alejandra Caffulli

Last update: 18 May, 2023

When they become pregnant, all women want to provide their children with all the medical care that’s within their reach to ensure their health and healthy development. If you’re expecting, keep reading and find out what prenatal diagnosis consists of and the great importance of performing it during pregnancy.

In order to monitor the proper formation and development of the fetus, a series of tests are performed during different stages of pregnancy that can save the lives of babies and their mothers. These tests are known as prenatal diagnosis. However, although some tests are the same for all women, others must be performed based on the condition of both the mother and the fetus.

What’s prenatal diagnosis during pregnancy?

The main objective of prenatal diagnosis is to monitor the correct evolution and development of the fetus. This, with the purpose of detecting and preventing possible diseases or frequent deformities during certain stages of pregnancy. It has been proven that most congenital defects occur during the first three months of gestation.

Due to the above, it’s highly recommended that expectant mothers have family health insurance so that they can have all the tests recommended by their gynecologist. And, in this way, they’ll be able to know together with their partner what the state of health of their little one is before the expected birth.

These are some of the common tests during prenatal diagnosis.

1. Ultrasounds. These are probably the most well-known non-invasive prenatal test for all expectant mothers and are performed throughout the pregnancy. From the second month, they help to diagnose possible malformations, and from the third month, they can detect markers of chromosomopathies.
2. Fetal DNA testing in maternal blood. This is one of the most frequent tests and is performed from the 10th week of pregnancy. The results show whether the fetus has a chromosomal abnormality; for example, Down syndrome or Edwards’ syndrome.
3. Amniocentesis (amniotic fluid test). In this test, an analysis of the amniotic fluid that surrounds the developing baby during the 15th and 20th weeks of gestation is performed in order to diagnose genetic disorders, birth defects, and other health problems. These include cystic fibrosis and Tay-Sachs disease.

What’s the incidence of congenital defects?

Prenatal diagnostic tests are indispensable throughout gestation, as they allow early identification of the vast majority of congenital defects that can affect fetuses. Early diagnosis before birth facilitates pre and post-natal care. Moreover, in extreme cases, it enables parents to decide whether to continue or terminate the pregnancy, either for the mother’s sake or because of future complications in the health of her child.

It’s estimated that congenital defects affect 5% of pregnancies. In such cases, the developing baby has an abnormality that, depending on its severity, may result in intrauterine death or physical or mental abnormalities at birth.

What’s the preparation for prenatal diagnostic testing?

This depends very much on the test to be performed. In the case of an imaging test such as ultrasound, there are no prior recommendations and the procedure is painless, as it’s a test designed not to cause discomfort or side effects.

However, in the case of an amniocentesis, certain instructions are necessary. For example, for the clinical analysis, you must be on an empty stomach and with a full bladder (if you’re at an early stage of pregnancy). This helps the uterus to move into a better position during the test. However, in later stages of pregnancy, you should come with an empty bladder.

During the test, the woman lies on her back on an examination table. Then, the attending professional moves a device known as a transducer over her abdomen, which uses sound waves to determine the position of the fetus and placenta. A needle is then inserted into the abdomen and a small amount of amniotic fluid is withdrawn for analysis. It’s a procedure that usually takes no more than 15 minutes.

Get prenatal diagnostic tests and take care of your baby’s health

Now that you know the importance of prenatal diagnosis to ensure the health of the mother and her baby, don’t hesitate to undergo all the tests recommended by your family doctor if you’re expecting a little one. Remember that a timely assessment can save your life in case of danger and allows you to know for sure that the pregnancy and fetal development are in perfect condition.