Down's Syndrome Screening

Being worried about your unborn baby’s health is completely natural, especially when it comes to conditions like Down syndrome. Down syndrome is a genetic condition caused by an extra chromosome, which can affect a baby’s development. While it may lead to physical, mental, and health challenges, many people with Down syndrome live happy, fulfilling lives with the right support.

At Apollo Cradle & Children’s Hospital, we offer screenings to assess the risk of Down syndrome during pregnancy, helping parents make informed decisions about their baby’s health and care.

Down Syndrome Meaning

Down syndrome is a genetic condition that happens when a person is born with an extra copy of a specific chromosome, called chromosome 21.

Chromosomes are tiny, thread-like structures found inside cells. They are made of proteins and a single molecule of DNA (Deoxyribonucleic Acid). Their main job is to carry genetic information—the instructions that help the body grow and work—and pass it from one cell to another.

Most people have 23 pairs of chromosomes, which means 46 in total. People with Down syndrome, however, have an extra copy of chromosome 21, so they have 47 chromosomes instead of 46. This extra chromosome impacts how the brain and body develop. It can cause physical differences, like a flatter face or smaller ears, and make learning and understanding things take longer. People with Down syndrome may also have some health issues, like heart problems or low muscle tone.

How Common is Down syndrome?

Down syndrome is the most common chromosomal/genetic condition worldwide. In India, about 1 in every 850 babies is born with Down syndrome. It is estimated that around 30,000 to 35,000 children in India are affected by this condition each year.

Different Types of Down Syndrome

There are three different types of Down syndrome:

• Trisomy 21:

This is the most common type of Down syndrome, making up about 95% of cases. In Trisomy 21, each cell contains three copies of chromosome 21 instead of two.

• Translocation Down Syndrome:

In translocation Down syndrome, there is an extra part or a full extra copy of chromosome 21, but instead of being separate, it is attached (or "translocated") to another chromosome. This type is less common and accounts for about 3% of Down syndrome cases.

• Mosaic Down Syndrome:

In mosaic Down syndrome, some cells have three copies of chromosome 21, while others have two. Because not all cells are affected, people with this type may show fewer characteristics of Down syndrome. Mosaic Down syndrome is the rarest type, occurring in about 2% of cases.

Although the types differ in how the chromosomes are arranged, the effects of Down syndrome are generally similar across all three types.

Signs & Symptoms of Down Syndrome

Down syndrome can lead to physical, behavioural, and mental symptoms. However, not everyone with this condition will experience all of these symptoms. The symptoms and effects of Down syndrome can differ from person to person.

Down Syndrome Physical Features

Some common physical features of Down syndrome include:

• A flat face, especially a flat nose bridge

• A short neck

• Almond-shaped eyes that slant upward

• Small ears, hands, and feet

• A tongue that often sticks out of the mouthy

• Small pinky fingers

• Shorter-than-average height

• Poor muscle tone or loose joints

• A single crease across the palm (palmar crease)

Behavioural Down Syndrome Symptoms

Children with Down syndrome may show behavioural symptoms because they might find it hard to express their needs to their parents. Some common behavioural signs of Down syndrome include:

• Stubbornness and tantrums

• Trouble with social interactions or understanding social cues

• Impulsiveness or difficulty controlling actions

• Trouble focusing or paying attention

• Strong attachment to familiar objects or routines

• Repeating certain actions or behaviors

• Sleep problems (difficulty falling asleep or staying asleep)

Cognitive Symptoms of Down Syndrome

A child with Down syndrome may face challenges with thinking and learning due to the extra chromosome. This can cause delays in reaching developmental milestones, such as walking or talking. Some areas that may be affected include:

• Walking/Moving

• Speaking

• Learning

• Playing

The symptoms of Down syndrome can be different for each person, but with the right support, many individuals with Down syndrome lead happy, fulfilling lives.

What Other Issues Can Down Syndrome Lead to?

While many people with Down syndrome share common physical features and lead healthy lives, some may experience health problems or birth defects. Some common health issues include:

• Frequent ear infections or hearing loss

• Vision issues or eye conditions

• Sleep apnea (a condition where breathing stops and starts during sleep)

• Heart defects present at birth (congenital heart defects)

• Digestive issues

• Dental problems

• Spine problems in the upper back or neck

• Obesity

• Higher risk of infections or illnesses

Healthcare providers carefully monitor newborns with Down syndrome for these health concerns, as they may lead to additional symptoms as the child grows.

Causes of Down Syndrome During Pregnancy

Down syndrome occurs because of an extra chromosome. Normally, each cell in the human body has 23 pairs of chromosomes, making a total of 46. In people with Down syndrome, there is a change in how chromosome 21 divides, which leads to an extra copy of this chromosome.

This means a person with Down syndrome has an extra chromosome 21 in some or all of their cells.

While we don’t know the exact cause of Down syndrome, certain factors can increase the chances of having a baby with the condition.

Some risk factors for Down syndrome include:

• The mother’s age : The risk is higher if the mother is 35 or older when she becomes pregnant.
• Having a child with Down syndrome already : Parents who have one child with Down syndrome have a higher chance of having another child with the condition.

Down Syndrome Diagnosis

Down syndrome diagnosis can be done during pregnancy through a series of screenings and diagnostic tests.

1. Down Syndrome Screening Tests

During pregnancy, screening tests are offered to all women to evaluate the chance of the baby being born with Down syndrome. If the pregnancy test for Down syndrome shows a higher risk, diagnostic tests may be recommended for confirmation.

Combined First Trimester Screening (Including NT Scan)

Screening for Down syndrome is typically done during the first trimester. It is important to note that these screenings are not diagnostic—they only estimate the likelihood of a baby having Down syndrome or other chromosomal conditions, such as trisomy 13 or trisomy 18.

The results of the NT measurement, nasal bone data, blood flow assessment, and blood test are combined with the mother’s age to calculate the overall risk of Down syndrome, trisomy 13, or trisomy 18.

• A positive result (high risk) does not mean a baby has Down syndrome but indicates the need for further diagnostic tests to confirm.

• A negative result (low risk) does not guarantee that a baby will not have a chromosomal condition.

It is important to remember that most babies are born healthy, even to mothers classified as high risk. These Down syndrome screenings provide valuable information to help parents make informed decisions about additional testing and care.

2. Diagnostic Tests for Down Syndrome

If a Down syndrome screening test shows a high risk, diagnostic tests can give a clearer answer. Here are the main diagnostic testing options:

Diagnostic tests like CVS and amniocentesis are over 99% accurate in determining if the baby has a chromosomal abnormality. Final results from chromosomal analysis may take 2-3 weeks, but preliminary results can often be available within a few days.

Some parents choose not to undergo further Down syndrome tests during pregnancy for various reasons:

• They may feel satisfied with the screening results and prefer not to have a definite answer.

• Diagnostic Down syndrome tests, like amniocentesis or CVS, come with a small risk of complications, such as miscarriage, which some parents may want to avoid.

Talk to your healthcare provider about the risks, benefits, and concerns to make the best choice for your family.

The Bottom Line

At Apollo Cradle & Children’s Hospital, we understand how important it is for parents to make informed decisions about their baby's health. Down syndrome screening is a key part of this process, helping to identify potential risks early on. While Down syndrome may present challenges, individuals with this condition can lead fulfilling lives, participating in school, work, and various activities just like anyone else. With the right care and support, they can achieve their fullest potential and bring joy to their families and communities.

If you're expecting and have concerns about Down syndrome, it's important to talk to a healthcare provider at the best maternity hospital to explore screening options and ensure the best possible care for you and your baby.

For more Down syndrome information or to schedule an appointment, call Apollo Cradle at 1860-500-4424 today.

We are here to connect you with the best paediatricians, leading obstetricians, and top gynaecologists who are ready to assist you and provide expert care for all your needs.

Request an appointment at Apollo Cradle, Call 1860-500-4424 to book an appointment.