When getting any screening, remember that there's a chance of false-positive or false-negative results:. Women whose results show a high risk for carrying a baby with a chromosomal abnormality are offered diagnostic testing, usually through chorionic villus sampling CVS in the first trimester or amniocentesis in the second trimester.
Those who are not shown to be high risk in the first trimester are still offered a second trimester screening. That screening, which consists of more blood tests, checks for chromosomal abnormalities and neural tube defects, and helps to confirm the findings from the first trimester screen.
The blood screening is usually done between 9 and 14 weeks. Women who also get an ultrasound have one between 11 and 14 weeks. Blood screening results usually are ready within a week or two. Ultrasound results can be immediate. When both the blood test and ultrasound are done, doctors usually calculate the results together.
This is called a combined first trimester screening. Not all doctors calculate a woman's risk this way. Some wait until after a woman has had other screenings in the second trimester. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions. Skip to navigation Skip to main content Site map Accessibility Contact us.
Search this site Search all sites Search. Go to whole of WA Government Search. Open search bar Open navigation Submit search. Treatments and tests. Facebook Youtube Twitter. Home Treatments and tests Screening tests in the first 3 months of pregnancy. Screening tests in the first 3 months of pregnancy You may wish to find out early in your pregnancy if your baby is at increased risk of a serious health condition by having a screening test in your first trimester the first 3 months of pregnancy.
The first trimester screening test is done between 9 weeks to 13 weeks 6 days of your pregnancy. How is the test done? The first trimester test involves 2 measurements: A sample of your blood is taken at a pathology collection centre between 9 weeks to 13 weeks 6 days of your pregnancy, but ideally between 9 to 12 weeks.
Changes in these levels can indicate a serious chromosomal condition. An ultrasound is done between 11 weeks to 13 weeks 6 days of pregnancy, ideally at 12 to 13 weeks.
This area, known as nuchal translucency, is often larger in babies with Down syndrome. This test only notes a mother is at risk of carrying a baby with a genetic disorder. Many women who experience an abnormal test discover later the test proved false. You will not be given specific quantitative values for the separate parts of the First Trimester screen.
Abnormal test results warrant additional testing for making a diagnosis. Your genetic counselor will discuss the results with you and assist you in deciding about diagnostic tests, such as CVS or amniocentesis.
These invasive procedures should be discussed thoroughly with your healthcare provider and between you and your partner. Additional counseling may prove helpful. First Trimester Screening will help find about 84 percent, or 5 out of every 6, babies with Down syndrome, and about 80 percent, or 4 out of every 5, babies with trisomy Performing further testing allows you to confirm a diagnosis and then provides you with certain opportunities:.
Some individuals or couples may elect not to pursue testing or additional testing for various reasons:. First-Trimester Screening. What is a first trimester screening test?
How is the first-trimester screen performed? What are the risks and side effects to the mother or baby? Why you might consider this test One advantage to having First Trimester Screening is that you will have information about your risk for Down syndrome and trisomy 18 earlier in the pregnancy than you would with the standard Maternal Serum Screening.
When is the first-trimester screen performed? What does the first-trimester screen look for? What do the results mean?
What are the reasons for further testing? Down syndrome, also called trisomy 21, is caused by an extra chromosome in the developing baby. It causes mental retardation and serious heart problems.
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