What is prenatal testing?
Prenatal testing performed during pregnancy helps physicians detect any congenital anomalies or genetic disorders in the fetus. If a screening test, such as ultrasound, is found to be abnormal or if there is a family history of a genetic disorder prenatal testing may be recommended.
DNA molecules are packaged into thread-like structures called chromosomes. Gene mutations occur due to changes to the DNA sequence, chromosomal structure, or number of chromosomes. Genetic aberrations play an essential role in many genetic disorders and can be inherited from parents or occur spontaneously during embryonic development.
With advances in human genetic research and analysis technologies, various types of causative genetic aberrations associated with disorders can be detected prenatally thus providing valuable information to aid parents, physicians, and genetic counselors in making the best decisions before and after birth.
Types of prenatal genetic tests
Prenatal genetic tests can be performed using DNA extracted from amniocytes (amniocentesis), chorionic villus sampling (CVS), or circulating fetal DNA (cfDNA). Genetic testing of cfDNA, unlike amniocentesis and CVS, is non-invasive since it is present in the mother’s blood.
Karyotyping, the traditional prenatal genetic test, is a low-resolution method that examines a picture of stained chromosomes. Because of its low resolution, certain genetic disorders, such as those with tiny mutations, can be missed by karyotyping.
DNA sequencing of cfDNA reduces the need for invasive procedures and can be beneficial for women diagnosed with high-risk pregnancies.
Benefits of prenatal testing
Prenatal testing provides information on the health of the mother and the baby during pregnancy and the baby’s risk of developing genetic disorders. Having this valuable information enables parents and their physicians to proactively manage both the mother’s and baby’s health during pregnancy and after birth.