Second trimester Down syndrome screening results

Generally speaking, medicine leaves room for interpretation of Down syndrome screening results: the fetus of a high-risk pregnant woman is not necessarily a Down syndrome baby; the fetus of a low-risk pregnant woman is not necessarily not a Down syndrome baby. The Down syndrome screening results at the hospital only indicate the probability of having a Down syndrome baby, not that there is definitely a problem with a high-risk baby. The result of Down syndrome screening is not a final diagnosis, but only the risk, that is, the possibility of suffering from Down syndrome. Further examination is necessary, such as amniocentesis, minimally invasive DNA, etc. before a diagnosis can be made.

How to judge the results of Down syndrome screening in mid-pregnancy?

When is the best time to do Down syndrome screening? This is what many mothers want to know. Only by finding the best time can the test be effective.

The early stage of pregnancy is 9-13 weeks, the second stage of pregnancy is 14 days to 21 weeks and 6 days, and the selection is 16-18 weeks. However, because the conditions of each pregnant woman and hospital are different, the actual time for Down syndrome screening should be consulted by the hospital. In addition, you need to learn to read the results of Down syndrome screening carefully. To determine the risk of Down syndrome screening, we focus on three indicators:

1. Reuters

High alpha-fetoprotein is a special blood protein in the fetus, and the standard value should be more than 2.5MoM. For pregnant women with congenital fetuses, the level of alpha-fetoprotein in the blood cells is 70% of that of normal pregnant women. The lower the measurement, the higher the chance of having Down syndrome.

MoM is the multiple of the median, which refers to the blood cell markers of pregnant women in prenatal diagnosis tests, and is the frequency of the median value of the blood cell concentration of all normal pregnant women.

2. Human chorionic glargine insulin (hCGβ)

The level of human chorionic gonadotropin in the blood cells of pregnant women with congenital epilepsy shows an increase. The higher the index, the higher the chance of suffering from Down syndrome.

3. Free estriol (uE3)

Free estriol is the main estrogen produced in the fetus, and the uE3 value of pregnant women with congenital fetuses is reduced.

Blood test values:

If the blood test screening value exceeds the national standard of 1/270, the pregnant woman is at high risk. High risk simply means that the possibility of a fetus with Down syndrome is higher, while the low-risk group may also develop Down syndrome.

It should be emphasized that the calculation methods of hospital outpatient services are not completely consistent, and therefore the standards are different. Generally, the standard value is about 1/700 and the national standard is 1/270. Below these two values, the risk is relatively low.