รู้หรือไม่? สตรีตั้งครรภ์ทุกคนมีโอกาสเสี่ยง..ลูกเป็นดาวน์ (Down Syndrome)

<p>Most children with Down syndrome are born due to an abnormality of chromosome pair 21, with 3 chromosomes instead of the normal 2 chromosomes. The total number of chromosomes becomes 47 (normal people have only 46 chromosomes). This condition results from an abnormality in the process of maternal germ cell formation during pregnancy.</p>
<h2 style="color: #008080;"><span style="color: #00826a;">Who is at risk of having a child with Down syndrome?</span></h2>
<p>All pregnant women are at risk, depending on various risk factors such as gestational age during pregnancy and a history of having a child with Down syndrome. The mother&#8217;s age during pregnancy is the main risk factor, especially mothers over 35 years old (counted until the due date), who have a significantly increased risk. The risk of having a child with Down syndrome in the second trimester is approximately 1:270, meaning that among 270 pregnant women, 1 has a chance of having a child with Down syndrome. This is a key indication for counseling and recommending diagnostic chromosome testing of the fetus, such as amniocentesis, chorionic villus sampling, fetal umbilical cord blood sampling, and screening for fetal chromosomal abnormalities from maternal blood, etc.</p>
<p>However, for pregnant women under 35 years old, although the percentage risk of having a child with Down syndrome is low, more than 70 percent of children with Down syndrome are born to younger mothers, who make up the majority of all pregnant women. Therefore, pregnant women under 35 years old should be screened to assess the risk of giving birth to a child with Down syndrome.</p>
<h2 style="color: #008080;"><span style="color: #00826a;">Various screening methods to detect Down syndrome</span></h2>
<ol>
<li><span style="color: #00826a;"><strong>Screening</strong></span> to identify the risk of having a child with Down syndrome, which can currently be done by several methods such as ultrasound to measure the thickness of the fluid accumulation under the fetal neck (NT: Nuchal Translucency), checking for the presence of the fetal nasal bone, and biochemical tests in maternal blood such as AFP, Free –βhCG, uE3.</li>
<li><span style="color: #00826a;"><strong>Diagnostic testing</strong></span> to confirm results by chromosome testing from amniotic fluid, chorionic villi, or fetal umbilical cord blood.</li>
<li><span style="color: #00826a;"><strong>Screening for fetal chromosomal abnormalities from maternal blood</strong></span> called Non-invasive Prenatal Testing (NIPT), which can screen for up to 15 common genetic disorders without the need for amniocentesis or chorionic villus sampling. This method is easy, convenient, safe for the fetus, and carries no risk of miscarriage. It can be performed from 10 weeks of gestation onwards and is applicable for singleton, twin, and IVF pregnancies.</li>
</ol>
<h2 style="color: #008080;"><span style="color: #00826a;">Current standard screening methods used today are screening in the first trimester or the second trimester (both trimesters can be tested)</span></h2>
<ol>
<li><span style="color: #00826a;"><strong>First trimester screening</strong></span> performed at 10-14 weeks of gestation: This assesses risk based on maternal age combined with biochemical markers in maternal blood, including PAPP-A, Free –βhCG (possibly combined with ultrasound measurement of nuchal translucency: NT for increased sensitivity).</li>
<li><span style="color: #00826a;"><strong>Second trimester screening</strong></span> performed at 15-18 weeks of gestation: This assesses risk based on maternal age combined with biochemical markers in maternal blood, including AFP, Free –βhCG, and uE3 (known as the Triple test), possibly including inhibin A.</li>
</ol>
<h2 style="color: #008080;"><span style="color: #00826a;">How to interpret screening results</span></h2>
<p style="color: #008080;"><span style="color: #00826a;"><strong>Abnormal screening result (positive result)</strong></span></p>
<p>When the overall risk is greater than 1:270*, a positive screening result does not mean the fetus definitely has Down syndrome but indicates a higher risk (for example, a risk of 1:50 means that among 50 pregnant women with similar blood test results, 1 fetus has Down syndrome and 49 are normal). It is recommended to perform chromosome testing of the fetus, similar to recommendations for mothers over 35 years old (the false positive rate is about 5%). (*The cut-off value depends on each institution.)</p>
<h2 style="color: #008080;"><span style="color: #00826a;">Normal screening result (negative result)</span></h2>
<p>When the overall risk is less than 1:270, a negative screening result does not mean the fetus cannot have Down syndrome but indicates a significantly reduced risk (for example, a risk of 1:1500 means that among 1500 pregnant women with similar blood test results, 1 fetus has Down syndrome).</p>
<p>Phyathai 2 Hospital uses first trimester maternal blood screening for Down syndrome (15-18 weeks) possibly combined with ultrasound measurement of nuchal translucency using globally accepted standard methods.</p>


Down Syndrome is a genetic disorder caused by chromosomal abnormalities and is the most common cause of intellectual disability. This chromosomal abnormality can occur in any pregnant woman.

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Did you know? Every pregnant woman has a risk of having a baby with Down Syndrome.

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