Prenatal Screening

Be informed about your baby’s health during pregnancy. Pregnancy is a wonderful time filled with excitement, curiosity, and anticipation of a new addition to the family. Early weeks of pregnancy is exciting and anxious too. Pregnant mothers would want reassurance that baby is normal and healthy.
At various stages of pregnancy, several tests are made to ensure that mother and baby are in a healthy condition and baby is developing normally.

What are Chromosome Conditions?

It occurs when there are extra or missing chromosomes or a rearrangement of pieces of chromosomes. Physical and intellectual development can be affected because of this. Down syndrome is the most common condition. People with down syndrome have 47 chromosomes instead of 46.

Why Prenatal Testing needed?

While most babies are born healthy, only 2 or 3 out of 100 newborns may have major birth defects. For the majority of defects, the cause is unknown. However, there are certain birth defects that can be tested in pregnancy before the baby is born.
The first-trimester screening popularly known as FTS is performed to rule out the possibility that you are at increased risk of having a baby with down syndrome, Trisomy 18 or Trisomy l3.

Understanding Down Syndrome?

In our country the baseline awareness of Down Syndrome is low and that for the screening test is even less. Down Syndrome is a Chromosomal abnormality where the child is born with an extra Chromosome 21. Down Syndrome occurs in about 600 to 700 pregnancies all over the world. Any women can have a baby with Down Syndrome. The risk varies with the mother’s age. 70% of babies with down syndrome are born to younger mothers and therefore screening is offered to all women.
Down syndrome results in developmental problems and a higher risk of conditions including heart defects, mental retardation, breathing and hearing problems and also childhood leukemia. The severity of these conditions varies greatly from individual to individual. No treatment is available for down syndrome. Counseling and support to manage the baby are the only hope.

What is Trisomy 18 and Trisomy 13?

Trisomy 18 and 13 are comparatively rare and severe forms of the chromosomal abnormality associated with severe developmental delay and a physical problem with life-threatening complications in a baby‘s first month and years. No treatment is available for Trisomy 18 or 13.

Performance of Prenatal Screening
Performance of Prenatal Screening

Why prenatal testing important?

Being tested during pregnancy allows you to be informed about the health of your baby even before birth.

How is prenatal screening performed?

Various methods are practiced. The screening can be done in the first trimester, second trimester or in both trimesters. The screening takes into account of mother’s age, a blood test and a special ultrasound test.

What is First Trimester Screening and when is it done?

Optimal time is from 11 weeks to 13 weeks 6 days. It involves a blood test and ultrasound. The ultrasound confirms your baby’s age and measures the amount of fluid behind the baby’s neck (Nuchal Translucency or NT Scan).
The first-trimester Nuchal translucency scan offers several additional benefits. Other abnormalities like cardiac anomalies, diaphragmatic hernia, skeletal dysplasia, abnormal lymphatic drainage, neuromuscular disorders are associated with increased NT. Hence detailed anatomic survey and fetal echo are needed.



What is Second Trimester Screening?

If the pregnant patient has missed the opportunity of first trimester screening. She should undergo second-trimester screening. Yet the detection rates for down syndrome is lower than FTS around 65-70%. Second Trimester Screening also checks for open neural tube defects such as spina bifida, a condition of improper development of the brain and spinal cord.

Post-test counseling:

Once the screening is done. The result is again explained. If screening is positive, then the details of invasive testing are discussed like amniocentesis or CVS (Remember, a screening test does not confirm the Chromosomal problem, a positive test should be followed by a confirmatory test).

Be sure to discuss these additional confirmatory test with your doctor. Most babies are born healthy. Early, more accurate screening gives peace of mind during pregnancy.