All You Need to Know about Prenatal Genetic Test

Prenatal Genetic Test

It’s on the rise that most health providers are likely to ask you about your knowledge about genetic tests. This happens when you make an early prenatal visit.

The test seeks to obtain the genetic information of your family or the one of your partner’s information. However, some partners find it wise to undergo this test before conception.

There are two main types of tests that help answer questions about you and your partner’s structure of genes. Remember, each test bears its risks, benefits, and shortcomings. The two tests are screening tests and diagnostic tests.

The screening tests will help unravel if the woman bears huge risks of suffering from gene diseases. The diagnostic test helps discover if or not a given condition can affect the pregnancy.

Prenatal Screening Tests

Health Conditions The Test Seeks To Determine

There are various conditions that an advanced test can help reveal. Here are the descriptions of the most notable ones.

Down syndrome – Some health expert will refer to it as trisomy 21. This is because it occurs when the excess copy of chromosome 21 causes Down syndrome. The key features of this disorder are mental retardation, heart defects, and some facial appearances.

Trisomy 18 – This condition is very deadly in babies who are under a year old. Its first characterization is mental retardation. The disorder occurs when an extra copy of chromosome causes the condition.

An open neural tube defect – This happens when babies are either born with an opening in the head or spinal cord. The openings in the two regions prevail as a result of the failure of failure of the neural tube to open.

In most cases, babies born with anencephaly (opening in the head) are either stillbirth or die soon after delivery. On the other hand,  newborns with an opening in the spinal cord (spina bifida) will need surgery that might result in paralysis.

The condition can be severe, but the daily intake of 400 micrograms of folic acid before conception can alleviate it.

Could there be cases of abnormality in the prenatal test?

The answer is a definite affirmative, but it shouldn’t cause any alarm as babies remain unaffected in many cases. Some lab tests indicate that out of a sample of 1000 serum screening test, the manifestation of an open neural tube defect can be 50.

Out of the 50 cases, only a paltry of two or one cases can have the condition.

Most labs that provide standard serum test will show nearly 2/3 of the fetus with Down syndrome among women of below 35 years. However, 9/10 women of above 35 years will show signs of Down syndrome.

The Ideal Time For Prenatal Test

The first prenatal test will involve a test of the pregnant woman’s blood test and an ultrasound test. The health experts do these tests in the first trimester of pregnancy (between 10-13 weeks).

The blood test aims to measure the level of two substances. The ultrasound (nuchal translucency screening) is used to measure the space at the back of the fetus neck.

Any abnormal measurement will mean a tremendous risk of Down syndrome or other types of aneuploidy to the fetus.

The second prenatal test takes place in the second trimester of pregnancy (between 15-22 weeks). The medical expert performs a test known as quadruple or simply quad’.

The test will measure the level of four different elements. The tests will further screen for Down syndrome, an open neural tube defect and trisomy 18.

There’s also a combined result of the prenatal test. This will combine the two results of two tests in both first trimester and second trimester of pregnancies.

The test is more accurate than either of the two on their own. However, it will take the time to have it as you must wait for the second-trimester test.

Prenatal Screening Test

Analysis Of The Abnormal Prenatal Screening Results

A positive screening result will mean that the fetus will have higher risks of suffering from aneuploidy. This doesn’t necessary mean that fetus will practically have the disorder.

A negative result will be good news as the fetus will have minimum chances of suffering from the disorder. You should not worry much because it doesn’t mean that the fetus can’t suffer from the disorder.

A suggestion might come from your health provider on whether to undergo diagnostic tests like Amniocentesis or CVS. The result of both tests is comparatively accurate than the earlier prenatal tests.

Many gynecologists prefer Amniocentesis to CVS as it tests for neural tube defect which the later can’t detect. The idea of a diagnostic test should come as a last resort as it’s complicated, risky and expensive.

Some factors to consider before this test are;

Availability of your family’s genetic information

If you previously had the last child with such defect

If you and your partner are carriers of the same disorder

You must be above 35 years old at delivery


This is one test that has become rampant with nearly all the pregnant women in the US involved.

It has benefits of helping the victims to have preparations in case your child has the disorder. You and your partner might altogether decide not to have children if you see the likelihood of the condition.

Also, the test can prove very risky and in most cases require counseling from health workers. The test isn’t mandatory but necessary for any couple.

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