What does Down syndrome screening mainly check?

The full name of Down syndrome screening test is prenatal screening test for Down syndrome. This test is very important and basically every pregnant woman has to do it before delivery. Down syndrome screening also combines the age of the pregnant woman and uses a computer to accurately calculate the risk of the pregnant woman carrying a fetus with Down syndrome. However, many people are not very clear about the content of Down Syndrome Secha. So, what does Down syndrome screening mainly check? Let’s take a closer look below.

What is Down syndrome screening?

Down syndrome screening refers to the prenatal screening test for Down syndrome. Its purpose is to test the concentration of alpha-fetoprotein, chorionic gonadotropin and free estriol in the maternal serum by testing the pregnant woman's blood, and combining clinical information such as the pregnant woman's age, weight, smoking status, and whether she has any disease to comprehensively calculate the risk of fetal congenital defects. The general accuracy rate is about 80%.

Is Down syndrome screening necessary?

Recommendation: Every pregnant woman should check

Down syndrome, also known as trisomy 21 or congenital idiocy, is a disease in which children have severe intellectual disability, are unable to take care of themselves and suffer from complex cardiovascular diseases. They require long-term care from their family members, placing a huge burden on the family. Since Down syndrome is a sporadic disease, every mother has the potential to give birth to a child with Down syndrome. Down syndrome serum screening is a very effective method to detect Down syndrome children, and it is recommended that every pregnant woman undergo Down syndrome screening.

Older pregnant women should not be ignored

Because the probability of a fetus developing congenital malformations such as Down syndrome is related to the mother's age, older pregnant women are particularly in need of Down syndrome screening. Studies have shown that if the pregnant woman is over 30 years old, the chance of the fetus developing Down syndrome is 1/1000. If the pregnant woman is over 35 years old, the chance rises to 1/300. For pregnant women aged 35 to 39, the chance is 1/50. If the pregnant woman is over 40 years old, the chance is as high as 1/20.

When is Down syndrome screening done?

The time period for Down syndrome screening is between 15 and 20 weeks of pregnancy, and the best time is between 16 and 18 weeks. The specific arrangement time of hospitals in different places is not certain, pregnant women can listen to the hospital's notification. When the Down syndrome screening index exceeds the normal value, the pregnant woman needs to undergo amniocentesis or chorionic villus sampling. Only when both results are normal can the possibility of the fetus suffering from Down syndrome be ruled out to the greatest extent.

How to perform Down syndrome screening

1. Consultation preparation

Down syndrome screening is related to the pregnant woman's menstrual cycle, body mass index, gestational age, and fetal age. It is best to consult your doctor for other preparations before the examination.

2. No need to fast before the examination, and venous serum of pregnant women is drawn during screening

The indicators of alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG) and free estriol (uE3) in maternal serum were detected.

3. Provide detailed personal information

Including date of birth, last menstrual period, weight, whether suffering from insulin-dependent diabetes, whether smoking, history of abnormal pregnancy, etc. Please note that Down syndrome screening is not currently applicable to those with in vitro fertilization or twin pregnancies.