Antenatal Screening For Genetic Disorders In Yet-To-Be-Born Baby

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..

Probable Risks

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

Biochemical Screening

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.

Second Trimester

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.

Diagnostic Tests

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.