{"id":730,"date":"2020-09-25T23:52:09","date_gmt":"2020-09-26T05:52:09","guid":{"rendered":"https:\/\/americanpregnancy.org\/?p=730"},"modified":"2021-12-09T13:36:07","modified_gmt":"2021-12-09T19:36:07","slug":"first-trimester-screening","status":"publish","type":"post","link":"https:\/\/americanpregnancy.org\/prenatal-testing\/first-trimester-screening\/","title":{"rendered":"First-Trimester Screening"},"content":{"rendered":"

The First-Trimester Screening<\/strong> is an early optional non-invasive evaluation that combines a maternal blood screening test with an ultrasound<\/a> evaluation of the fetus to identify risks for specific chromosomal abnormalities, including Down Syndrome Trisomy-21<\/a> and Trisomy-18.<\/p>\n

In addition to screening for these abnormalities, a portion of the\u00a0test (known as the nuchal translucency) can assist in identifying\u00a0other significant fetal abnormalities, such as cardiac disorders. \u00a0The screening test does not detect neural tube defects.<\/p>\n

What is a first trimester screening test?<\/h2>\n

It is very important to remember what a screening test is before\u00a0getting one performed. This will help alleviate some of the anxiety\u00a0that can accompany test results. Screening tests do not look only\u00a0at results from the blood test<\/a>.\u00a0 They compare a number of different\u00a0factors (including age, ethnicity, results from blood tests, etc\u2026)\u00a0and then estimate what a person\u2019s chances are of having an abnormality.<\/p>\n

These tests DO NOT<\/strong> diagnose a problem; they only signal further\u00a0testing should be done.<\/p>\n

How is the first-trimester screen performed?<\/h3>\n

The blood screen involves drawing blood from the mother, which takes\u00a0about 5 to 10 minutes. The blood sample is then sent to the laboratory\u00a0for testing. The ultrasound is performed by an ultrasound specialist\u00a0or perinatologist and takes between 20 and 40 minutes. The results\u00a0are evaluated\u00a0within a week of the testing.<\/p>\n

What are the risks and side effects to the mother or baby?<\/h3>\n

Except for the discomfort of drawing blood, there are no known risks or side effects associated with the First Trimester screen. There is a 5% false-positive rate for the test. Parents should be aware of the possibility of receiving abnormal results and then finding, after further testing, the baby is normal.<\/p>\n

Why you might consider this test<\/h3>\n

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<\/a>. While both First Trimester and Maternal Serum Screening can test for Down syndrome and trisomy 18, Maternal Serum Screening can also test for neural tube defects.<\/p>\n

When is the first-trimester screen performed?<\/h3>\n

The First Trimester Screen is performed between the 11th<\/a> and 13th\u00a0week of pregnancy<\/a>. Because the test is performed so early, it is often\u00a0used to determine whether a mother should consider undergoing an early\u00a0(first-trimester) diagnostic test, such as chorionic villus sampling<\/a>, or second-trimester amniocentesis<\/a>.<\/p>\n

What does the first-trimester screen look for?<\/h3>\n

In babies who are at an increased risk for chromosomal abnormalities, increased fluid is often found in the nuchal translucency. Abnormally high or low hCG and PAPP-A levels are also often found. The first-trimester screen combines the results from these three measurements (nuchal translucency, hCG, and PAPP-A) with maternal age risk factors and determines an overall risk factor for chromosomal abnormalities.<\/p>\n

What do the results mean?<\/h3>\n

It is important to remember the first-trimester screen is a screening test and not a diagnostic test. 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.<\/p>\n

You will not be given specific quantitative values for the separate\u00a0parts of the First Trimester screen. Instead, you will be told whether\u00a0your results are \u201cnormal or abnormal\u201d, and you will be\u00a0given a risk level by your genetic counselor. The counselor will give\u00a0you your risk factor for chromosomal abnormalities based on the test\u00a0results (for example 1\/250, 1\/1300).<\/p>\n

Abnormal test results warrant additional testing for making a diagnosis. \u00a0Your genetic counselor will discuss the results with you and assist\u00a0you in deciding about diagnostic tests, such as CVS<\/a> or amniocentesis.<\/a>\u00a0These invasive procedures should be discussed thoroughly with your\u00a0healthcare provider and between you and your partner. Additional counseling\u00a0may prove helpful.<\/p>\n

What are the reasons for further testing?<\/h3>\n

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 18.<\/p>\n