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Paternity Test During Pregnancy

Updated: Mar 26

Prenatal Paternity Test

When a couple is trying to conceive a baby, there's always the question of whether or not their partner was involved in the conception. While most fathers take the news well, some couples choose to use paternity tests to ease their minds before bringing a child into the world.

There are two types of prenatal paternity tests:

  • Non-invasive prenatal testing

  • Invasive prenatal testing

Test de paternité prénatal

Non-Invasive Prenatal Paternity Test

The non-invasive prenatal paternity test can be performed with a simple blood sample from the mother and a saliva sample from the presumed father. The laboratory determines the parentage by comparing the fetal DNA present in the blood to the presumed father's genetic profile. This painless and non-hazardous technique for both the mother and the baby provides precise results at 99%.

However, the test is not infallible, and the accuracy of the results depends on the amount of DNA from the baby that the laboratory can extract from the blood sample. Generally, the analysis is possible from the 7th week of pregnancy and anytime thereafter. But, depending on the candidates, it may happen that the mother's blood sample does not provide enough genetic information from the baby to establish a comparison with the father. This is a variable that is challenging to predict for laboratories, which always offer the option to analyze another blood sample taken two weeks after the first if such a situation arises.

This can occur when the mother faces challenges during her pregnancy or has medical history. Moreover, just because your samples do not provide enough fetal DNA does not necessarily mean there is a problem with your pregnancy. Monitoring involves clinical, biological, and ultrasound examinations to ensure the mother's well-tolerance and the fetus's proper development. There is no generalization in genetics, and each situation must be studied case by case.

Invasive Prenatal Test

Invasive sampling methods, such as amniocentesis, CVS (Chorionic Villus Sample), or trophoblast biopsy, involve taking tissue samples from amniotic fluid, placenta, or the umbilical cord.

These procedures are invasive as they represent a surgical operation and can pose a risk of pregnancy loss. Nevertheless, the risk of miscarriage remains very low, less than 1%.

However, laboratory results are still more accurate than non-invasive prenatal paternity tests because they provide more tissue samples to analyze. The quantity of markers allows determining whether there is a genetic match between the presumed father's DNA and that of the baby. It also provides the opportunity to know the baby's gender and genetic predispositions.

Indeed, invasive prenatal tests are generally recommended for expectant mothers at high risk of having a child with a genetic disease. Tests can indicate whether your baby is affected by conditions such as Down syndrome, for example. Moreover, it is recommended that fetal anomaly screening be based on parental history, the mother's age, and biological and ultrasound results to establish a diagnosis. If you are considering an invasive test, discuss with your doctor the advantages and disadvantages of each type of test before making a decision.

In conclusion, it is also possible and less expensive to wait for the child's birth to perform a paternity test by directly comparing the DNA present in the participants' saliva. This can allow you to conduct a test with legal value, useful in legal or administrative proceedings, which may not be the case with a result from a prenatal test.


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