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DNA Testing While Pregnant (should you)

Updated on October 22, 2021
Medically Reviewed by
Dr. Dhingra
Written by
Joel
2 sources cited
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Have you considered DNA testing before your baby is born? You aren’t the only one. Many mothers test during pregnancy to rule out medical issues. DNA testing is also used to determine the biological father of an unborn baby.

What are three things you should know about DNA testing while pregnant?

1. Why is DNA Testing Before a Baby is Born Useful?

A lot of mothers aren’t sure if they can undergo DNA testing while pregnant or why it’s something they might want to do.

The truth is you can have a test and there are several reasons why you might want to do so.

You can learn a lot about your baby with DNA testing. One of the most common uses for DNA testing before birth is to identify the father of a child. Knowing who the father of your child is helps you make decisions about financial issues and allows you to include the father in your preparations and the birth of your child. Keep in mind, to get accurate results from a DNA test for paternity, three samples need testing: the mother, the father, and the baby.

Keep in mind, even if you know who the father of your baby is, some states require an unmarried couple to have a paternity test in order to list the father’s name on the birth certificate. Additionally, if the mother is legally married to someone who is not the father, that person is presumed the father by law without a DNA test proving otherwise.

DNA testing is also used before and after a baby is born to identify health issues. These tests allow you to determine what genetic risks your baby faces. Knowing in advance the health issues that might arise once your baby is born helps you prepare for what’s to come.

2. Is DNA Testing before a Baby is Born Safe?

For the most part, DNA testing during pregnancy is safe, but there are some risks. This is especially true if you are undergoing invasive DNA testing during pregnancy. There are two types of invasive tests used during pregnancy.

The first is Chorionic Villi Sampling (CVS). It is usually performed between the tenth and thirteenth weeks of pregnancy and involves taking cells from the placenta using a long, hollow needle inserted through the abdomen.

The second testing method is Amniocentesis. This type of test is usually performed between the fourteenth and twenty-fourth week of pregnancy. It involves taking the fetal cells released into the amniotic fluid using a long needle inserted into the abdomen.

The risks of these types of DNA tests include:

  • Cramping
  • Leaking of amniotic fluid
  • Vaginal bleeding

The other faces the greatest amount of risk, but there is a slight risk of harming the unborn baby or miscarriage. A doctor performs invasive DNA testing, so you’ll have a chance to discuss your risks before deciding to undergo the test.

Non-invasive DNA testing during pregnancy is far less risky. These tests use a cheek swab or blood sample instead of withdrawing amniotic fluid. They are primarily used to test for paternity.

Non-invasive tests:

  • Eliminate fetal risk
  • Are an option as early as the ninth week of pregnancy
  • Offer results in as little as five days
  • Have a 99.9% success rate of determining paternity

In these tests, a blood sample is taken from the mother and the man who is potentially the baby’s father. The test isolates fetal DNA signals in the mother’s sample, which are then compared to the potential father’s sample. The results from this method of testing are not considered legally admissible, but they can help you determine if there is a cause for additional testing.

3. Is DNA Testing While Pregnant Affordable?

Many of the tests available to expectant mothers are not covered by health insurance. This means anyone who wants these tests must pay out-of-pocket – something that isn’t always possible when you’re already thinking about the costs of raising a child.

The good news is DNA testing can be affordable depending on the type of test you use.

Costs will vary, depending on the type of test. Tests tend to range from $400.00 to $2,000.00. Non-invasive prenatal testing can cost more than a test performed after a baby is born, so if the cost is an issue and you can wait, you’ll pay less. If you prefer to test before birth, some testing facilities offer payment plans so you can undergo testing, but you might need to pay in full before receiving the results.

There are lower-cost tests that offer results that are not legally admissible. Some people call these “curiosity tests.” Tests such as this can be used in a variety of situations, but an example of one use would be if a couple is using IVF and natural methods to conceive a child and they want to confirm if the baby is from donated sperm or the father.

To learn more about DNA testing while pregnant or to schedule a test, contact your doctor or a testing facility that can provide you with more information.

DNA Testing While Pregnant: What You Should Know

If you’re wondering if DNA testing while pregnant is safe, what kind of DNA testing is best when you’re pregnant, and whether you should consider a DNA test, read on to learn more.

Consumer DNA testing requires you to submit a sample you get from a cheek swab for testing. Some DNA tests use a blood sample. However, cheek swabs aren’t an option for babies in utero and testing blood is a bit more complicated when you take the sample from a pregnant woman.

Your DNA remains the same over your lifetime. You get half of your DNA from your biological mother and biological father. This is why paternity testing reveals information about a child’s biological father.

What happens when you are pregnant is that your blood mixes with the baby’s blood. Your baby produces unique blood and that blood blends with yours through the umbilical cord and placenta while pregnant. Waste that travels from your baby through the umbilical cord “taints” your genetic material. This means there are traces of your baby’s blood, and therefore your baby’s father’s blood, mixed with yours while pregnant.

Blood samples tend to be very reliable for DNA testing, but this isn’t the case when a woman is pregnant. Most commercial DNA tests cannot tell the difference between the blood of the baby and the blood of the mother.

However, the information gleaned from testing the mother’s blood provides a great deal of information about the baby’s genetic material. There’s more reason to have your blood tested for information about your baby than there is to test your blood for your genetic information when pregnant. In most cases, your doctor will test the amniotic fluid in addition to your blood when conducting a DNA test while pregnant.

The best option you have if you want information about your DNA while pregnant, use a test that doesn’t require a blood sample. Blood-based DNA tests might be inaccurate because your blood is tainted by your baby’s blood while pregnant. 

DNA Testing for a Baby’s Father

If you need to prove a biological link to your baby’s father, DNA testing is possible even before your baby is born.

The most important thing to understand is that you can’t use an at-home DNA test to legally prove paternity. Paternity tests to use during pregnancy include:

Noninvasive Prenatal Paternity (NIPP) takes a blood sample from the baby’s presumed biological father and the mother. These samples are compared to determine if the father’s cells appear in the mother’s bloodstream. These tests have an accuracy rate of 99 percent or more and work as soon as the eighth week of pregnancy.

Amniocentesis is an invasive test. A sample of DNA in the amniotic fluid is compared to a sample of DNA collected from the presumed biological father. Performing amniocentesis carries with it a small risk of miscarriage. Doctors perform this test between the 14th and 20th weeks of pregnancy.

Chorionic Villus Sampling (CVS) is an invasive test. It takes a sample of tissue attached to the uterine wall and compares it to the presumed biological father’s DNA. Performing CVS carries with it a higher risk of miscarriage than amniocentesis. Doctors perform this test between the 10th and 13th weeks of pregnancy.

DNA Testing for Medical Issues

Some people conduct DNA testing while pregnant to determine whether their baby has any medical issues. The most common type of DNA testing used for this purpose is prenatal cell-free DNA (cfDNA) screening. This is sometimes called noninvasive prenatal screening. It recognizes chromosomal abnormalities in the growing fetus.

The test sample is obtained by extracting DNA from the mother’s blood, which includes both the mother and the baby’s DNA. This sample is screened for an increased chance of chromosomal problems, including trisomy 13, trisomy 18, and Down syndrome. Additionally, this test might reveal other genetic abnormalities, including:

  • Trisomy 16
  • Trisomy 22
  • Triploidy
  • Sex chromosome aneuploidy
  • Certain disorders caused by a chromosomal deletion (microdeletion syndrome)
  • Certain single-gene disorders

You can also determine a baby’s gender using this testing method. Doctors perform this test at the 10th week of pregnancy or later. This test tends to be more sensitive than other DNA testing methods during pregnancy. It’s also less risky than other testing methods, including CVS and amniocentesis.

Unfortunately, prenatal cell-free DNA screening is unreliable if a woman is:

  • Pregnant with twins/multiples
  • Obese
  • Pregnant via a donor egg
  • A gestational carrier
  • Using certain blood-thinning medications

Section 4: Prenatal DNA Tests

In addition to the cfDNA test, there are other types of prenatal genetic testing offered to most women during pregnancy. For example:

Quad or Triple Screen

This test has been used for many years and is available during the 15th and 20th weeks of pregnancy. The test analyzes the mother’s blood for up to four different hormones. The test shows potential risk of Down syndrome, trisomy 18, and spina bifida. 

First Trimester Screening/Ultrascreen

This is a newer test that is more accurate than quad or triple screen tests. It’s also available earlier in pregnancy. It uses ultrasound measurement, nuchal translucency, and a blood sample from the mother. The test shows potential risk of Down syndrome, trisomy 18, and trisomy 13.

Keep in mind, these tests are not 100 percent accurate. They have a high accuracy rate, but they cannot guarantee your child does or does not have a genetic abnormality.

Section 5: Non-Prenatal DNA Tests

There is also a non-invasive prenatal DNA test. These tests pose less of a risk to the baby, but the results from these tests have a lower accuracy rate.

Non-invasive testing uses a fragment of DNA from the placenta to screen for fetal aneuploidy. It’s considered a legitimate alternative to the quadruple screening test. It can be used alone or in combination with the screening.

In addition to prenatal DNA tests, there are many reasons to test DNA when not pregnant. The three most common types of non-prenatal DNA tests include:

  • Y-DNA testing: assesses the chromosomes in the Y chromosome
  • Autosomal DNA testing: measures 22 pairs of chromosomes
  • Mitochondrial DNA (mtDNA) testing: uses a tiny snippet of DNA stored in the mitochondrial

Resources

SHOW
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Chorionic Villus Sampling. 8 Mar. 2019, https://www.mayoclinic.org/tests-procedures/chorionic-villus-sampling/about/pac-20393533

“Amniocentesis: Purpose, Procedure and Risks.” Healthline, 2012, www.healthline.com/health/amniocentesis

Dr. Dhingra
Dr. Harshi Dhingra
Medical Reviewer
Dr Harshi Dhingra is a licensed medical doctor with a specialization in Pathology. Dr. Dhingra has of over a decade in diagnostic, clinical, research and teaching work, including managing all sections of Pathology laboratory including histopathology, cytology, hematology and clinical Pathology.
Joel
Content Contributor
Joel is a writer with a passion for the science of DNA and the power of its manipulation.
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