Many parents want to know if their unborn child might have any genetic abnormalities, and prenatal genetic screening tests confirm them. When a woman learns that she is pregnant, doctors recommend several tests to get information about the baby’s health quickly. This led to an early decision about the prenatal genetic screening test.
Genetic screening tests before pregnancy are optional, which can help you detect the risk of abnormalities in a child and can provide you additional information before a baby’s birth.
With prenatal screening for genetic disorders, we can get large amounts of genetic information about the pregnancy from a simple blood draw. Although the results can help families make an informed decision about the pregnancy, some tests do not give a definite result.
Why are Prenatal genetic Screening tests important?
Blood-based screening tests are not diagnostic tests that can show for certainty that the baby is affected. They have to be taken in combination with other tests to know the likelihood of genetic abnormality in the child.
But prenatal genetic tests can give you a good idea about your baby’s health. Therefore, you should always talk about any type of testing before your baby is conceived. Most people would like to talk about what they would do if the test results were positive so that they were on the same page before the baby’s arrival.
Pregnancy screening options
Most women have their personal choices whether to undergo or decline screening for a variety of reasons. There are two blood-based screening methods to detect chromosome abnormalities in pregnancy:
First-trimester screening: Before pregnancy, the hormones in a mother’s blood are screened in this genetic screening test. An ultrasound test is done to measure the back of the baby’s neck, also known as a translucency scan. The test detects an extra fluid on the neck, which could also be a sign of Down syndrome or other heart complications.
Prenatal screening for genetic disorders also screens for other chromosome abnormalities and can sometimes detect the likelihood of complications such as poor growth in pregnancies.
Cell-free DNA screening: In this test, the blood is drawn from the mother, where the DNA fragments from the placenta are used to identify high-risk pregnancies. This test is highly sensitive to screen for Down syndrome, trisomy 13, and trisomy 18. Usually, there’s a very low false-positive rate, but it does not confirm genetic disorders in the baby.
Diagnostic testing in pregnancy
There are also diagnostic tests that provide more accuracy and information about the genetic disorders in the baby. These tests move beyond the common chromosomal problems and can detect smaller deletions or duplications. These are usually effective when those prenatal genetic screening tests have come as positive.
Some of the options include:
Chorionic villus sampling: A small placenta tissue is extracted from the service using a needle. A test is usually conducted between the 10th and 13th week of pregnancy.
Amniocentesis: In this test, amniotic fluid of the baby is extracted through the abdomen. The amniotic fluid, mostly the baby’s urine, contains the fetal cell that is helpful for diagnostic testing. This test is usually conducted between 15 weeks into the pregnancy or at a later stage.
However, there is a slight risk of miscarriages with these procedures, but this phenomenon is very rare for the right testing laboratories.
After the genetic test before pregnancy test results, patients with abnormal screening results are sent to a genetic counsellor to provide psychosocial training and prepare them about what lies ahead for them if they want to continue with the pregnancy.
