Re-evaluation of risk for Down syndrome by means of the combined test in pregnant women of 35 years or more

Abstract

The application of the combined test reduced the need for invasive testing to only 14% of the studied pregnant population, without missing any of the fetuses with trisomy 21 or 18.

Beyond Trisomy 21: Additional Chromosomal Anomalies Detected through Routine Aneuploidy Screening

“…Trisomy 18 was the most frequently reported condition in eligible studies. Data was obtained from 61 studies, including 30 that utilized the first trimester combined test [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ], 17 that used the second trimester triple screen [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ], 12 that contained data on NIPT [ 40 , 41 , 42 , 43 , 44 , 45 , 70 , 71 , …”

First-trimester screening: lessons from clinical trials and implementation

“…Compared to pregnant women under 35 years of age, the greater prevalence of Down's syndrome in older gravidas increases the detection rate but at the expense of a much higher screen-positive rate [10,19], which can be 25-100% for women over 39 years of age [10,28]. Even with optimal performance, first-trimester screening cannot lower the risk of all aneuploidies below 1% for gravidas over 40 years of age.…”

Should cell‐free fetal DNA be included in first trimester screening (FTS) for common trisomy? A possible scenario on 6697 women screened over 10 years

“…In 2007, the Health Authority of the Tuscany Region announced the application of the first trimester combined test to the entire obstetrics population, based also on clinical experience from a modified clinical strategy carried out in the Tuscany Region. The primary aim of this policy was to standardize the criteria for gaining access to prenatal diagnosis through calculation of individual risk for common trisomy based on a combination of NT and biochemistry (free β‐hCG and PAPP‐A) and to offer invasive procedures (CVS and/or amniocentesis as second choice) to high‐risk women (>1:250) regardless of maternal age. There are now convincing evidences that a strategy based on the first trimester combined test results in earlier diagnosis of fetal malformations and chromosomal abnormalities, thus allowing earlier termination of pregnancy, and also reduces the number of fetal invasive procedures and, as a result, of related fetal losses.…”