World Down Syndrome Day 2018: is your baby at the risk of Down syndrome?

in your prenatal stage, your doctor will talk about various diagnostic check-ups to ensure the status of your health and that of your unborn baby. One important reason is to check for a chromosomal abnormality like Down syndrome.

World Down Syndrome Day 2018 is on March 21.

It s a general observation that the vast majority of babies born are normal, devoid of genetic abnormalities. However one should remember that all women, whatever their age, have a small risk of delivering a baby with a physical or mental handicap or both. In some cases the handicap is due to a chromosomal abnormality giving rise to a condition like Down syndrome, says Dr Shantala Vadeyar, consultant obstetrician, fetal & maternal medicine, specialist, Kokilaben Dhirubhai Ambani hospital.

The nuchal translucency scan or the NT scan conducted somewhere between the 11 and 13 weeks of pregnancy is an important scan done to assess the risk if the fetus has chances of developing Down s syndrome. Know more about the importance of NT scan.

What is Down syndrome?

Down syndrome is a chromosomal disorder caused by an error in the process of cell division. The condition leads to impairment in both cognitive ability and physical growth that ranges from mild to moderate developmental disabilities in the baby. Through a series of screenings and tests, Down's syndrome can be detected before and after a baby is born. Early detection of this disorder during pregnancy gives the expectant couples a chance to manage their pregnancy and prepare for any eventuality in advance.

Is your baby at risk?

Of the many factors that could affect the baby with this disorder, maternal age is one of them. Though there are other factors that can contribute to be potential risk factors for your unborn baby. Factors that can stand to be of a probable cause for your baby to suffer from this disorder are as follows:

Age of the mother: It is usually seen that for mothers less than 30 years of age one in 1000 pregnancies can result in a baby with Down s syndrome whereas for mothers who are 44 years of age and above about 1 in 23 pregnancies result with a baby with Down s syndrome.

Amount of fluid behind the neck of the fetus: The amount of fluid present at the back of your baby s skin under the neck is called nuchal translucency. This measure also stands to be indicative if your baby is at risk of Down s syndrome. A reading less than 3.5 mm for a fetus who measures 45 mm to 85 mm from crown to rump is considered to be off the dangers of the disorder. Lower the reading means lesser the chances of your baby being born with this disorder.

Presence or absence of nasal bone: The nuchal translucency test also looks for the presence of a nasal bone. It is seen that fetus that show the presence of a nasal bone during the NT scan has reduced chances of having the disorder.

Levels of two hormones PAPP-A and hCG: Mothers with higher level of hCG and lower levels of PAPP-A stand a chance to bear a fetus with risk of having Down s syndrome.

Though the above mentioned factors can help in detecting the risk of Down s syndrome, there are other markers also that help in estimating the risk of this chromosomal disorder such as the fetal heart rate, the blood flow through the fetal heart and liver and more. But the NT scan is not only the diagnostic test that calculates the risk in the unborn baby. Other marker tests or blood test couple with the results of an NT scan gives an accurate estimation. Know more about the test you need to take during your first trimester to make sure your pregnancy is safe and healthy.

After the NT scan on the basis of all the above factors, the estimated risk of Down s syndrome will be discussed with the expectant couple. Also options for invasive diagnosis tests are offered, but it depends on the couple if they wish to go for it, informs Dr Vadeyar. Irrespective of whether or not you decide to have an invasive test, it is recommended that you have a scan at 20 weeks to check for physical abnormalities. It is important to have this scan and risk assessment done by experts who are correctly trained and certified in this technique and are using the software that is of a high standard. Even though these markers and risk factors can account for the probability of a baby being born with Down s syndrome but it can at times also show false positive results too.

Read to know about the other tests that you need to take during your second and third trimester apart from the 20 week anomaly scan to be sure about the fetal wellbeing.

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The only way to do be sure if your baby is suffering from Down s syndrome is to go for an invasive test if your NT scan spells danger signs. A CVS or chorion villus sampling test is conducted taking tissues from the placenta to check for Down s syndrome and other chromosomal abnormalities. Also amniocentesis is done by collecting the fluid from the amniotic sac to test for the same. Both these tests are invasive and can give a accurate status of the fetal wellbeing. However these tests also carry a risk of miscarriage of about 1 percent. As a norm an invasive test is usually offered id the risk of Down s syndrome is 1 in 300 or above, says Dr Vadeyar.

Discuss the pros and cons with your doctor before you opt for these tests to check for the probability of Down s syndrome.