Genetics counseling and chorionic villus sampling or amniocentesis should be offered to all women with elevated risk, as determined by serum screening. Women with isolated nuchal thickening or isolated maternal serum AFP (with normal ultrasonography and normal karyotype) should be followed closely because they are at increased risk of poor pregnancy outcomes.Ĭombined first- and second-trimester screening offers superior detection rates while maintaining low false-positive rates. Quadruple screening is recommended for second-trimester screening. Pregnant women should be offered screening and invasive diagnostic testing regardless of age.Ĭombined testing is recommended for first-trimester screening. Specific screening tests will depend on availability of the procedure and patient preference. Comprehensive counseling should be available to all pregnant women. For women who do not present until the second trimester, the quadruple screen is recommended. If nuchal translucency testing is unavailable, the maternal serum-integrated test is safest and most effective. An integrated test with nuchal translucency testing is the most effective method for women who present in the first trimester. These options include an analysis of pregnancy-associated plasma protein A, with or without nuchal translucency testing, in combination with quadruple screening. Patients may also choose a combination of first- and second-trimester screening in an integrated, stepwise sequential, or contingent sequential fashion. Screening options in the second trimester include serum screening using triple or quadruple screening, and ultrasonography. Nuchal translucency testing alone is not as effective. Screening options in the first trimester include nuchal translucency testing in combination with measurement of pregnancy-associated plasma protein A and human chorionic gonadotropin. Diagnostic options include chorionic villus sampling in the first trimester and amniocentesis in the second trimester. New developments in screening methods have increased the number of options for patients. However, many providers will have their patients who did NIPT get a blood draw in the second trimester for AFP, which is one of the markers on serum screening, that can screen for neural tube and abdominal wall defects since that’s something NIPT cannot screen for.Pregnant women of all ages should be offered screening and invasive diagnostic testing for chromosomal abnormalities before 20 weeks’ gestation. So if you’re going to do NIPT, you don’t do the first trimester blood draw for serum screening. We do not do both the integrated screen and NIPT together because you’re more likely to get a false positive if you do that (specifically because false positives are so common with serum screening). NIPT can also be done any time after 10 weeks (some people say 9, but you’re more likely to get low fetal fraction doing it that early) up until delivery. NIPT has a much higher sensitivity and specificity than serum screening. Some labs offer microdeletion panels as well, but the specificity of those are low so I personally prefer not to order them for my patients (that’s what that very misleading New York Times article is referring to). NIPT can screen for T13, T18, T21, and sex chromosome aneuploidies. NIPT analyzes bits of fetal DNA (actually from the placenta) circulating in the maternal bloodstream. Serum screening has to be drawn in very specific timeframes (once in the first trimester and once in the second) or else it’s not accurate. It can screen for trisomy 18, trisomy 21, Smith Lemli Opitz syndrome, and open neural tube defects/abdominal wall defects. to give a high risk versus low risk result. Serum screening (such as sequential integrated screen) incorporates the level of specific markers in your blood and other information such as maternal age, weight, race, etc.
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