If the screening shows a high risk for Down syndrome, will the baby be born with problems?

"The Down syndrome screening is high risk, the baby born will definitely have problems!"

The day before yesterday was "World Down Syndrome Day". When some mothers saw that the Down syndrome screening showed a high risk, they thought that there would definitely be problems with their baby after it was born.

Rumor Analysis

This statement is not rigorous.

Some pregnant women may show a high risk in the Down syndrome screening, but it does not mean that there must be something wrong with the baby. It just means that the risk of the fetus suffering from Down syndrome is increased and needs continued observation or further examination.

Down syndrome, also known as trisomy 21, is the most common chromosomal disease. It is caused by an extra chromosome 21 and may cause a series of physical and intellectual development problems.

Down syndrome patients have severe, irreversible intellectual disabilities, cannot take care of themselves, and need long-term care. They are often called "Down syndrome children" or "Down babies". The incidence of Down syndrome is 1/800 to 1/600. As Down syndrome is one of the most common genetic abnormalities, early identification of high-risk individuals is crucial.

Prenatal screening and prenatal diagnosis are effective ways to prevent Down syndrome. Down syndrome screening (abbreviated as Down screening) is a key pregnancy test used to assess whether the fetus is at risk of developing Down syndrome or other chromosomal abnormalities, such as trisomy 18 (Edwards syndrome).

So if the Down syndrome screening indicates “high risk”, does that mean there must be something wrong with the fetus?

Down syndrome screening high risk

Is there something wrong with the fetus?

Let me first state the conclusion. The fact that some pregnant women show a high risk of Down syndrome screening does not necessarily mean that there will be something wrong with the baby. The results of Down syndrome screening are based on data analysis and only indicate a certain possibility, not a confirmed report.

The so-called "high risk" result only means that the probability of a pregnant woman having a Down syndrome baby is higher than that of the general population. This assessment result is usually presented in the form of a ratio (such as 1:100) and is not a confirmation of chromosomal abnormality. Down syndrome screening is only a screening method, not a diagnostic report.

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Simply put, the results of Down syndrome screening will be affected by many factors such as the age of the pregnant woman, the number of weeks of pregnancy, and the level of specific markers in the blood, resulting in certain deviations. Therefore, in the face of high-risk results, the most reasonable step is to conduct further examinations to confirm whether there is indeed a chromosomal problem.

In fact, many fetuses that show high risk in Down syndrome screening can rule out related risks through further examinations, and they do not carry any chromosomal abnormalities after birth. Therefore, there is no need to be overly anxious if they are found to be "high risk".

Is it okay if the Down syndrome screening result is passed?

Some people may think that if their Down syndrome screening results are passed, their children will be fine. A Down syndrome screening result means that the possibility of the fetus having chromosomal abnormalities is low, but it does not completely eliminate all risks.

Down syndrome screening is a pre-screening method, not a diagnostic method, so even if the result shows "low risk", it does not mean that there is no risk at all. "Low risk" results mean that the fetus is less likely to have the disease relative to the set risk threshold (such as 1:270).

However, in a few cases, even if the Down syndrome screening shows a low risk, subsequent examinations (such as major fetal malformation screening) may still reveal abnormalities. At this time, further diagnostic tests, such as amniocentesis, are often required to confirm whether there is a chromosomal abnormality.

The first Down syndrome screening result was not good

Would it be more accurate if I go to a bigger hospital and do it again?

Repeating the Down syndrome screening test and transferring it to a larger hospital may not necessarily provide more accurate results. The accuracy of Down syndrome screening is affected by many factors, not just the location of the test. Since the redo test still uses the same biochemical markers and calculation methods, repeating the test may not necessarily bring more accurate results.

Therefore, if the initial Down syndrome screening results indicate a high risk, it is recommended to conduct more in-depth diagnostic testing rather than simply repeating the Down syndrome screening. Repeated testing may only slightly increase the detection rate and may cause some pregnancies that are actually high-risk to be misclassified as low-risk, thereby missing the opportunity for further diagnosis.

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Down syndrome screening

What should I do if the test shows high risk?

When faced with a high-risk result from a Down syndrome screening, staying calm is the first priority. Although this result may be cause for concern, it does not mean that the disease has been confirmed.

Usually, your doctor will recommend further testing based on your situation to get a more accurate diagnosis. These tests include non-invasive prenatal testing (NIPT), which analyzes fetal DNA in the pregnant woman's blood for risk assessment. Although it is more accurate, it is still a screening test. In addition, invasive diagnostic tests such as amniocentesis or chorionic villus sampling can provide a definitive diagnosis.

It is recommended that you seek genetic counseling before undergoing these tests to understand the significance of the test and possible consequences. In addition, it is equally important to obtain psychological support during this period, which can help you cope with the uncertainty and anxiety while waiting for the results.

Looking in the mirror of rumors

As the saying goes, too much worry leads to confusion. Pregnant mothers are particularly concerned about the health of their babies. If there is anything wrong with any examination, they will be worried. This feeling is understandable. We can learn more about the relevant knowledge and understand that screening is just a quick and simple test and inspection method to find possible problems. After that, more accurate diagnostic tests are needed to make further conclusions. In many cases, there are risks during screening, and further examinations will eliminate this risk. Therefore, we should calm down first, follow the doctor's advice to do further examinations, and then make plans based on the results.

References

[1] UpToDate: Down syndrome: Overview of prenatal screening.

[2] Norton ME, Jelliffe-Pawlowski LL, Currier RJ. Chromosome abnormalities detected by current prenatal screening and noninvasive prenatal testing. Obstet Gynecol. 2014 Nov;124(5):979-986. doi: 10.1097/AOG.0000000000000452. PMID: 25437727.

[3] Hackshaw AK, Wald NJ. Repeat testing in antenatal screening for Down syndrome using dimeric inhibin-A in combination with other maternal serum markers. Prenat Diagn. 2001 Jan;21(1):58-61. PMID: 11180243.

[4] Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders. Obstet Gynecol. 2016 May;127(5):e108-e122. doi: 10.1097/AOG.0000000000001405. PMID: 26938573.

Author: Weng Ruopeng, attending physician, Zhejiang University Affiliated Obstetrics and Gynecology Hospital

Reviewer: Lan Yibing, deputy chief physician, Department of Obstetrics and Gynecology, Zhejiang University Hospital