While the screening tests for Down syndrome and trisomy 18 can also be tested for serum, the screening can also be for neural tube defects. It is important to remember that the screening test for the first quarter is a screening test and not a diagnostic test.
The first-terminal screening is an optional and early non-invasive evaluation that combines a maternal blood screening test with an ultrasound exam of the fetus to identify risk for specific chromosomal abnormalities, including Down syndrome trisomy-21 and trisomy 18.
In addition to screening for these abnormalities, a part of the test (known as nuchal translucency) can help identify other significant fetal anomalies such as cardiac disorders. The screening test does not detect neural tube defects.
What is a first trimester – Screening test?
It is very important to remember what a screening test is before performing it. This will help ease some of the anxiety that may accompany test results. Screening tests do not focus on only the results of the blood test. They compare a number of different factors (including age, ethnicity, results from blood tests, etc…) and then estimate what one is chance of having an abnormality.
These tests DO NOT diagnose a problem, they only indicate that further testing should be performed.
How is performed the first quarter screen?
The blood screen involves the mother s blood taking up to 5 minutes to take. The blood sample is then sent for testing to the lab. Ultrasound is conducted by an ultrasound specialist or perinatologist and lasts between 20 and 40 minutes. The results are evaluated within a week of the test process.
What are the risk and side effects for mother or baby?
Except for the irritation of bringing blood, there are no known risk or side effects associated with the First Trimester Screen. For the test, there is a 5% false positive rate Parents should be aware of the possibility that they receive abnormal results and then discover the baby is normal after further testing.
The reason why you might consider this test?
One advantage of having a first trimester screening is that you will have information about your risk for Down syndrome and Trisomy 18 earlier in pregnancy than with standard hemiplegic screening. While both the first trimester and maternal serum screening can test for Down syndrome and trisomy 18 the maternal serum screening can also test for neural tube defects
When is performed the first trimester screen?
What does the first three-word screen look like?
What do the results mean?
It is important to remember that the first quarter screening test is a screening test and not a diagnostic test. This test only provides information that a mother is at risk of carrying a child with a genetic disorder. Many women who experience an abnormal test later find that the test has proven false.
You will not receive specific quantitative values for the separate sections of the first trimester screen. Instead, you will be told whether your results are “normal or abnormal”, and by your genetic counselor you will be given a risk level. Using the test results (for example 1/250, 1/1300), the counselor will give you your risk factor for chromosomal abnormalities.
Abnormal results warrant additional tests for a diagnosis. Your genetic counselor will discuss the results with you and will help you decide on diagnostic tests such as CVS or amniocentesis. These intrusive procedures should be thoroughly discussed with your provider and between you and your partner. Further advice may prove helpful.
What are the reasons for a further test?
The first trimester screening will help with finding about 84 percent, or 5 out of 6 babies with Down syndrome and about 80 percent, or 4 out of 5 babies with Trisomy 18.
- Down syndrome, also known as trisomy 21 is caused by an extra chromosome in the developing baby. It causes mental retardation and severe heart disease. From 600 births is born a baby with Down Syndrome. Although having a child with Down syndrome occurs more frequently to women who are older, it can occur at any age.
- Trisomy 18 is caused in developing babies by an extra chromosome. To naryadomy 18 survive hardly babies. One child is born to trisomy 18 in every 6,000 Trisomy 18 causes mental retardation, heart failure, very poor growth and other problems.
Further testing allows you to confirm a diagnosis and then provide certain chances :
- Pursue potentially existing interventions (i.e. Fretrial surgery for Spina bifida
- Plan a child with special needs
- Start treating anticipated lifestyle changes.
- Find support groups and resources
- A decision about carrying the child to term will be made.
For different reasons, some individuals or couples may choose not to perform testing or additional testing:
- They are confident with the results, no matter what the outcome is.
- Taking a decision about children’s potential pregnancy to term is not an option because of personal, moral or religious reasons.
- Some parents choose not to allow testing that poses a risk to the baby development that is not approved by the state.
- It is important to discuss the risks and benefits of testing thoroughly with your health care provider. Your healthcare provider will help you assess if the benefits could exceed any risks of the procedure.
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Compilated utilizing the following sources of information: