Posted on 14th April, 2023 at 6:36:30 AM
Down syndrome is a chromosomal defect known as trisomic 21 which can occur in babies. Trisomic-21 defect can take place when various chromosomal changes take place just after the egg and the sperm meet.
Characteristics of a Down’s Baby
So what is a down baby, you may sometimes come across babies who are cute-looking babies but have very short noses, chubby cheeks, slightly protruding tongues, and slanting eyes. These babies generally have varying degrees of mental retardation. In certain babies, the mental retardation might be very less and the baby might be pretty smart. However, in some cases, a downs baby might be very slow to learn. It can be difficult for parents to bring up these babies, as they need a lot of financial and emotional support to help these children come up in life.
The risk of having a downs baby is higher in mothers who are older than 35 years. Nonetheless, downs can still occur in babies, with mothers less than 35 years old. Hence, at Thanawala’s we advise all our expectant mothers to undergo a Downs screening test.
Preliminary testing for Downs syndrome
These tests are done in the 1st trimester when the pregnant woman comes for an 11-13th week scan. The Downs screening test has two components.
Sonography is done to assess the structure & anatomy of the developing fetus. At the same time, we also see the nuchal thickness (the thickness of the skin behind the neck).
Blood tests to looks for hormonal changes that can suggest there is a problem with the baby’s chromosomes.
This nuchal thickness along with the gestational age & mother’s weight & age combined with the blood test result is entered into a computer program that gives us a risk report. if the report suggests a low risk of downs (i.e 1in 400 or 1 in 500) there is no need for further testing. However, if this report suggests a high risk of downs (i.e. 1 in 100) further testing for downs will be required to assess if the baby in question will have downs or not.
Further testing of Downs syndrome:
To confirm that the baby in question will have downs we now need to do an invasive test like a Chorion villus biopsy or Amniocentesis.
Chorion villus biopsy: For this biopsy a small tissue sample of the placenta is extracted by an ultrasound-guided very thin needle which is completely harmless to the baby.
Amniocentesis: At times we take a sample of the amniotic fluid and Look for the fetal cells.
Once the sample is extracted we need to culture them to get the exact karyotype of the baby. If the Karyotype is that of a Down baby then we can confirm that the baby will have Down syndrome.
Generally, parents who do not want a Downs baby and would want to terminate their pregnancy if the baby has Downs need to go for further testing.
Testing for Downs syndrome in the 4th-5th month of pregnancy
If a couple misses the Down syndrome test in the 1st trimester they can still test for Down in the 4th-5th month of pregnancy. This testing is done using a triple marker test or a quadruple marker test. These tests are not as effective as the 1st-trimester screening. These tests have an accuracy of 65% while the 1st-trimester tests have an accuracy of 95% in identifying downs.
Noninvasive prenatal testing (NIPT): NIPT is a non-invasive highly sophisticated method with a 99.9% accuracy of identifying downs. Even if the NIPT report comes out negative the baby does not have downs and no testing is required. However, if the report comes out to be positive, then we still have to do the invasive tests to prove the baby has downs and only then take a decision to abort the downs baby.
Cost of Downs Syndrome Testing
The cost of the 1st test is between Rs.2500/- to Rs.3000/-.
NIPT: Approx. Rs. 30,000/-
Chorion Villus Biopsy or Amniocentesis: Approx. Rs.30,000/-
