No Down syndrome screening is required for the second child

When pregnant with your first child, you will basically know what kind of examinations you need to do when you are pregnant with your second child. There are many items in pregnancy check-up, and the same check-up needs to be repeated when you are pregnant with your second child. However, many pregnant women think that their conditions are normal after some examinations and wonder whether they should be re-examined, such as Down syndrome screening. So, is it possible not to do Down syndrome screening for the second child? Let’s take a look below.

Down syndrome screening is a serum biochemical screening for fetal chromosomal abnormalities by drawing peripheral blood from the mother during the 16th to 18th week of pregnancy. Down syndrome screening is required for both the first and second child. The Down syndrome screening requires pregnant women to be under 35 years old, and those whose due date is under 35 years old can undergo Down syndrome screening.

If the pregnant woman is over 35 years old, she cannot do Down syndrome screening. Most pregnant women who are expecting their second child are older. She can choose to do fetal DNA testing in the maternal peripheral blood, which is the so-called non-invasive DNA, or she can choose to do amniocentesis for chromosome karyotype analysis. Amniocentesis and chromosome karyotype analysis are currently the gold standard for diagnosing fetal chromosomal abnormalities, but they are somewhat traumatic and may cause risks of bleeding, infection, miscarriage, etc. Pregnant women should make their choice based on their own circumstances.

Why do we need Down syndrome screening?

Down syndrome is an autosomal abnormality genetic disease, the main manifestations of which are severe intellectual disability, strange facial features, wide-set eyes, thick skin on the neck, etc. The patient is completely unable to take care of himself. The disease cannot be cured throughout life and will bring heavy mental and financial burdens to the family.

Any pregnant woman may have a baby with Down syndrome, and current medicine cannot cure Down syndrome. Measures to control the occurrence of Down syndrome mainly focus on preventing or reducing the birth of children with Down syndrome. In order to prevent the birth of children with Down syndrome, early detection and early treatment are very important, and prenatal Down syndrome screening is very important. But it should be clear that the purpose of screening is to screen out people who are more likely to have a certain disease, not to diagnose. If the screening shows a high risk, further examination is needed.

How to read the Down syndrome screening results?

Many mothers are confused when they get the results of Down syndrome screening, "18-Trisomy 1:800; 21-Trisomy 1:1100---what do these values ​​mean?" In fact, you don’t have to care about those values, just look at the screening results directly, which will show "low risk" or "high risk".

Low risk: It is less likely that the fetus will have Down syndrome.

High risk or borderline risk: There is a greater chance that the baby will have Down syndrome. But don’t worry too much, high risk does not necessarily mean that the fetus will be deformed. Down syndrome screening has a certain false positive rate, and the true positive rate for high-risk individuals who are ultimately diagnosed is only 1%-2%. Mothers whose screening results show high risk or critical risk need to undergo further examinations under the guidance of a doctor to confirm the diagnosis.