Antenatal Screening For Genetic Disorders In Yet-To-Be-Born Baby
Created by Dr. Surbhi Saini Updated on Nov 25, 2020
Every pregnant mom is concerned about the well-being of her baby in the womb. To ensure to-be-born’s health and status, it’s important to identify any risks in form of a disorder. A screening test called 'antenatal screening' is meant for this purpose. What risks could a yet to be born face? Let’s have a look at the probable risks:
Why Prenatal Genetic Screening Test
What does Antenatal Screening test for Genetic Disorders in Yet-To-Be-Born Baby? Check this..
There are various disorders such as Down’s Syndrome, Fragile X Syndrome, Cystic Fibrosis, and Edward syndrome that might become a reality for the yet to be born. Here are some of the probable causes for a baby to develop a disorder:
- Maternal risk factors
- Maternal age younger than 15 or older than 35yrs
- Weight (pre-pregnancy weight under 40 kgs or obese)
- History of complications during previous pregnancies
- Bleeding during the third trimester
- Rh incompatibility
- Gestational diabetes
Fetal Risk Factors
- Exposure to infection
- Exposure to addictive substances(cigarette smoking, alcohol intake)
- Pregnancy is considered at high risk when antenatal tests indicate that the foetus has a serious health problem such as a heart defect.
Antenatal Screening test for Genetic Disorders for Yet-To-Be-Born Baby
In this test, a single specimen of blood is drawn from the pregnant mom between her 1st and 2nd trimester within a span of 8 to 22 weeks of gestation. This test helps in detecting Down Syndrome and open neural defects.
First Trimester Tests
Free beta human chorionic gonadotropin (free beta-hCG) - elevated levels used to elevate to screen for fetal Down Syndrome.
PAPP-A (pregnancy-associated plasma protein-A) - it is one of the most crucial blood makers during this phase, as low levels of these were found to be associated with chromosomal abnormalities.
Alpha-fetoprotein (AFP) - high levels indicate fetus at high risk of neural tube defects such as spina bifida or anencephaly.
Estriol- low levels of estriol indicates for an increased risk of Down Syndrome. additional to estriol other two markers AFP and HCG together formed a panel of markers called “triple screen”
Inhibin – A- it can be useful in predicting miscarriages, Down Syndrome, pre-eclampsia and fetal growth restriction.
20-week ultrasound- it is done to examine the baby in a safe way looking for the risks of multiple birth defects like heart defects, cleft palate, kidney problems, limb anomalies as well as genetic disorders like Down's Syndrome.
Chorionic Villus Sampling(CVS) - this is performed in the first trimester. The main reason to undergo this test is to check and determine whether or not the baby has a normal number of chromosomes (46)or any kind of aneuploidies.
Amniocentesis - this is performed in the second trimester. This test also helps determine whether the number of chromosomes is normal and also for birth defects.
Cordocentesis- it is highly accurate during the second trimester and used to diagnose birth defects.
In case the diagnosis reports are positive, you should see a specialist as soon as possible. You should also speak to a Gynecologist and a Pediatrician to understand what should be the next steps and take an informed decision accordingly.