Women who will be 35 or older on their due date are at higher risk for a group of birth defects called chromosome disorders. A screening test can give you more information about your chance to have a Prenatal Screening Tests baby with this type of birth defect. If you want a Options for women screening test during pregnancy, you can decide 35 or older which one seems right for you.
How risk There are two main screening tests that look for birth defects: "State changes with age screening" and "NIPT". Either test can indicate if your pregnancy has a high or low chance for the baby to have a common chromosome disorder. Most Chance for Down syndrome pregnancies with Down syndrome and trisomy 18 can be found by starting with a screening test; however, screening tests occasionally miss these 25 year old 1 in 1250 30 year old 1 in 900 conditions. 35 year old 1 in 365 For women who will be 35 or older: 40 year old 1 in 100 • State screening detects 91-94% of babies with Down syndrome and trisomy 18 45 year old 1 in 30 • NIPT detects 98-99% of babies with Down syndrome and trisomy 18
State Screening NIPT State Screening is a more general test for birth NIPT is a more targeted screening test that looks for defects. This test estimates the risk for Down common chromosome disorders. This test estimates syndrome and trisomy 18, and can help find the risk for Down syndrome, trisomy 18, trisomy 13 pregnancies with certain physical birth defects. State and sex chromosome disorders. You can learn more Screening may also flag a pregnancy when there are about these conditions on our website: other rare conditions. State Screening usually includes http://genetics.kp.org. NIPT does not screen for any two blood tests, one in the first trimester and one in other chromosome conditions or birth defects. NIPT is the second trimester. This screening test can also done with a single blood test during the first or second include an optional ultrasound called NT ultrasound. trimester in pregnancy. NIPT sometimes shows a high NT ultrasound is done as a separate visit in the first risk result in healthy pregnancies, but this happens trimester of pregnancy. Women who have NT much less often than it does with State Screening. ultrasound and the first blood test get an early You are more likely to have a high risk result as you (preliminary) result for Down syndrome and trisomy get older because the chance of a chromosome 18. The NT ultrasound also offers early detection of disorder is higher. About 3% of the time NIPT shows some physical birth defects, although many physical a high risk result. Many of these pregnancies are birth defects cannot be seen until later in pregnancy. found to have a chromosome disorder. There are also State Screening uses your age to help determine the a small number of women who do not get any result chance for a chromosome disorder. You are more from NIPT. This happens more often earlier in likely to have a State Screening result that needs pregnancy or in women who are heavier. No results follow-up as you get older. State screening indicates a can be due to many reasons, such as a broken tube, a "high risk" about 15% of the time in women who are technical problem in the lab, or a chromosome 35 or older, but most of these pregnancies are found disorder in the baby. Repeat testing sometimes gives to be healthy. a result, but other testing is offered when NIPT is not successful. Genetics.kp.org © 2014, The Permanente Medical Group, Inc. All rights reserved. Regional Genetics Department (Revised Jan 2016) This information is not intended to diagnose or to take the place of medical advice or care you receive from your physician or ADA Review July 2018 other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. Prenatal Screening Tests Options for women 35 or older
If you choose to have a screening test…
You only need ONE of these two screening tests and you can choose which one you prefer to start with. State Screening and NIPT use very different methods to look for birth defects, but they test for many of the same conditions . Most women get reassuring results regardless of which screening test they choose. If you get a result that show s a high risk in your pregnancy, you will be offered follow-up through the Genetics department. However, sometim es a screening test shows a high risk even when the baby is healthy (false positive result). Taking both tests increases the chance of getting a false positive result and is NOT recommended.
Below you will find a comparison chart looking at the features of each screening test. State Screening NIPT
• General testing for birth defects • Targeted testing for age-related birth defects • Screens for common chromosome disorders • Screens for common chromosome disorders and certain physical birth defects • Multi-step testing: Two blood tests and an • Single blood test optional NT ultrasound • First blood test and NT ultrasound are done • Can be done in either the first or second in the first trimester; second blood test is trimester done in the second trimester • Earliest possible result 11 to 14 weeks • Earliest possible result 11 to 13 weeks (only when NT ultrasound is included) • Detects 91-94% of pregnancies with Down • Detects 98-99% of pregnancies with Down syndrome and trisomy 18 (detection rate syndrome and trisomy 18; also detects most varies by age). May help find rare pregnancies with trisomy 13 and sex chromosome disorders and genetic chromosome disorders conditions NOT found with NIPT • Offers early detection of some physical birth • Does not screen for any birth defects except defect with NT ultrasound. chromosome disorders • More likely to have a positive result - about a • More likely to have NO result - about a 1-2% 15% chance for women 35 or older chance regardless of age
A second trimester ultrsound is done in all pregnancies to screen for physical birth defects.
Talk with your OB provider if you have questions about your prenatal testing options.
© 2014, The Permanente Medical Group, Inc. All rights reserved. Regional Genetics Department (Revised Jan 2016) This information is not intended to diagnose or to take the place of medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor.