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#Afp test done second sequential screening pdf#

New developments in screening methods have increased the number of options for patients.

#Afp test done second sequential screening pdf#

Have abnormalities involving chromosome 21ĭownload pdf version of Brigham Obstetrics and Gynecology Sequential Integrated Screening Test information sheet.Pregnant women of all ages should be offered screening and invasive diagnostic testing for chromosomal abnormalities before 20 weeks’ gestation.

Have had a baby with Down syndrome already.

Life expectancy for a person with Down syndrome is about 50 years.ĭown syndrome may affect any pregnancy but some women are at higher risk than others, including those who: Children born with Down syndrome typically have moderate to severe intellectual disability, a characteristic physical appearance (flat face, slanting eyes), and other health problems. There are also rare cases when a parent carries a subtle abnormality on chromosome 21 that is passed to a child and causes Down syndrome. In most cases of Down syndrome, there is an extra copy of chromosome 21, giving that person 47 chromosomes instead of the usual 46. Each child inherits 23 chromosomes from the mother and 23 from the father, for a total of 46. Genes direct all the cells' activities, including growth, development and body functions. Normally, a person has 46 chromosomes, each of which are made up of thousands of genes, which are located inside all cells in the body. What is Down syndrome?ĭown syndrome, also called trisomy 21, is the most common chromosomal abnormality in newborns, occurring in about one of every 700 births. Note that screening tests cannot diagnose or rule out specific conditions so a screen negative result does not mean your baby will not be born with Down syndrome, it means that the chances are low. Your integrated screening results are considered "screen negative" if the risk for Down syndrome is less than one in 110 (for example, 1 in 150 or 1 in 200). What does a negative result for Down syndrome mean? It's important to note that five out of every 100 women who take the integrated screening test receive "screen positive" results but most will not have a baby with Down syndrome.

We will then offer you an amniocentesis test to examine your baby's chromosomes. If your results are "screen positive," your baby has a higher risk for Down syndrome than other babies.

Your integrated screening results are considered "screen positive" if the risk for Down syndrome is one in 110 or greater (for example, 1 in 90 or 1 in 80). What does a positive result for Down syndrome mean? We send a copy of the test results to your physician and a genetic counselor will call you to discuss the results and schedule any necessary follow-up appointments. We can also use the screening results to estimate the risk for other disorders including open neural tube defects (spina bifida) and Trisomy 18.The integrated screening results are usually ready one week after the second stage. The NT measurement, the levels of the five substances in your blood and your age help us estimate your risk of having a baby with Down syndrome. We combine the results from the first and second stages into a single screening result. A nurse will take a second blood sample to measure the amount of four proteins in your blood – alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3), and inhibin-A (inhA).The second stage is ideally performed at 15 or 16 weeks of pregnancy and no later than 22 weeks.A nurse will take a blood sample to measure the amount of pregnancy associated plasma protein-A (PAPP-A).We will perform an ultrasound to precisely determine how far along you are in your pregnancy and to measure the thickness of your baby's uncial translucency (NT), which is a fluid-filled space at the back of the baby's neck.One of our genetic counselors will meet with you, review your medical history and explain the test.The first stage is ideally done between 11 and 12 weeks of pregnancy, but any time between 10 and 13 weeks is acceptable.The test is performed at the Prenatal Diagnosis Center in two stages: There are different ways to test for Down syndrome screening but the Integrated Test is the most specific, has the highest detection rate and a low false-positive rate. The Integrated Screening Test tells you what the chances are that your baby might have Down syndrome or open neural tube defects such as spinal bifida.