Title: How to read the results of Down syndrome screening
Down syndrome screening is an important prenatal test during pregnancy, mainly used to assess the risk of the fetus having Down syndrome (trisomy 21). Many expectant mothers are often confused by the data and terminology on the report after receiving the screening results. This article will explain the results of Down syndrome screening in detail to help you better understand the report content.
1. Basic principles of Down syndrome screening
Down syndrome screening is done by drawing the blood of pregnant women, detecting specific biochemical markers in the serum, and comprehensively calculating the risk of the fetus having Down syndrome based on the age, weight, gestational age and other factors of the pregnant woman. Common screening indicators include:
| Indicator name | normal range | abnormal meaning |
|---|---|---|
| Free β-hCG | 0.5-2.0MoM | Higher levels may indicate increased risk |
| PAPP-A | 0.5-2.0MoM | Lower levels may indicate increased risk |
| AFP | 0.5-2.5MoM | Abnormalities May Suggest Neural Tube Defects |
2. How to interpret the Down syndrome screening report
Down syndrome screening reports usually include the following key information:
| Reporting items | Description |
|---|---|
| risk value | For example, 1:1000 means that among 1,000 pregnant women with the same conditions, there may be 1 child with Down syndrome. |
| cutoff value | Usually 1:270, higher than this is high risk |
| Single indicator value | Display the actual detection value of each biochemical marker |
3. Suggestions for handling different risk outcomes
Depending on the screening results, the doctor will give corresponding suggestions:
| risk level | Risk value range | Recommended actions |
|---|---|---|
| low risk | Below 1:1000 | Routine prenatal check-up, no further testing required |
| critical risk | 1:270-1:1000 | Non-invasive DNA testing recommended |
| high risk | higher than 1:270 | Amniocentesis is recommended for diagnosis |
4. Factors affecting the accuracy of screening results
The accuracy of Down syndrome screening is affected by many factors:
1.Accuracy of gestational age calculation: Wrong gestational age will directly affect the result judgment.
2.Maternal age: The older you are, the higher your basic risk value is.
3.weight: Being overweight or underweight will affect marker concentration
4.twin pregnancy: Requires special calculation methods
5.assisted reproductive technology: Risk calculations may need to be adjusted
5. Things to note after screening
1. Down syndrome screening is only a risk assessment, not a diagnostic test
2. High-risk results do not mean that the fetus is definitely abnormal and requires further diagnosis.
3. Low-risk results cannot completely rule out the possibility of Down syndrome
4. The best time for screening is 11-13 weeks + 6 days of pregnancy (early screening) or 15-20 weeks (mid-term screening)
5. If you have any questions, please consult a professional doctor in time
6. Comparison between Down syndrome screening and other examinations
| Check type | Detection rate | risk | cost |
|---|---|---|---|
| Down syndrome screening | 60-90% | Non-invasive | lower |
| Non-invasive DNA | 99% | Non-invasive | higher |
| amniocentesis | 100% | Invasive (0.5-1% miscarriage risk) | high |
Down syndrome screening is an important part of prenatal care. A correct understanding of the screening results can help expectant mothers make reasonable prenatal care decisions. It is recommended that pregnant women fully communicate with their obstetricians after receiving the report and choose the most suitable follow-up examination plan based on their personal circumstances.
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