Noninvasive prenatal genetic testing (NIPT) is a method used to analyze the risk that a fetus may have a chromosomal abnormality that will result in physical and/or mental developmental delays. Using a blood sample from the pregnant woman, scientists look at DNA present in the mother’s blood, including DNA associated with the pregnancy, and analyze the chromosomes for abnormalities. It is important to note that prenatal genetic testing is not a diagnostic test and that the results will only give your doctor information as to the risk that your child might have a trisomy disorder. If the results of the screening show a high risk of having a child with a chromosomal abnormality, the doctor may recommend a diagnostic testing for a more definitive answer. The thing to note about diagnostic testing is that it is a more invasive option.
Noninvasive prenatal screening tests for various conditions that can affect the health of your baby. However, the most common reason parents to be get these screening tests done is to learn more about the risks for certain trisomy disorders: Down syndrome, Edwards’ syndrome, and Patau syndrome. These conditions are called trisomy disorders because they all emerge as the result of an individual inheriting a third, partial or whole, copy of a specific chromosome.
Down Syndrome (trisomy 21)
Approximately 6,000 babies are born with Down syndrome in the United States each year. Down syndrome is the result of an individual inheriting an extra partial or whole twenty-first chromosome.
Individuals born with Down syndrome experience physical complications, such as abnormalities in heart structure, hearing loss, and conditions involving the hormones and glands in addition to delays in cognitive development. The risk of developing serious health complications is also higher in individuals with trisomy 21. However, thanks to medical advancements, many individuals diagnosed with Down syndrome live to age 60 and beyond, and significantly contribute to their communities.
Edwards’ Syndrome (trisomy 18)
Edwards’ syndrome occurs when an individual inherits an extra partial or whole 18th chromosome. In the United States, 1 in 2,500 pregnancies are affected by Edwards’ syndrome. Of those pregnancies, 1 in 6,000 result in a live birth.
The physical abnormalities associated with trisomy 18 are more severe than those related to Down syndrome. Children with Edwards’ syndrome require full-time medical care, and many do not live past their first year. However, in some cases, where symptoms are not as severe, some individuals have been documented to live into their twenties and thirties.
Patau Syndrome (trisomy 13)
Patau syndrome is among the rarest and most severe of trisomy chromosomal disorders. Patau syndrome is also called trisomy 13, because affected individuals inherit an extra partial or whole thirteenth chromosome.
The complications associated with Patau syndrome are so grave that the average time of survival is seven days. Abnormalities in the structure of the heart, abnormalities in the structure and development of the brain and/or spinal cord, and seizures are just a few of the health complications that a child with Patau syndrome can experience. Although many of these can be fatal, recent studies have shown that more children with trisomy 13 are living longer than one year of age.
Learning More about Noninvasive Prenatal Genetic Testing
If you would like to learn more noninvasive prenatal genetic testing, talk to your doctor or a genetic counselor. These healthcare professionals will help you understand if you are at risk of giving birth to a child with a genetic disorder and if any testing is recommended.