We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Genetic sonography after first-trimester Down syndrome screening.
- Authors
Krantz, D.A.; Hallahan, T.W.; Macri, V.J.; Macri, J.N.
- Abstract
Objective Approximately 90% of Down syndrome cases are detected during first-trimester screening. We aimed to determine the potential effectiveness of second-trimester genetic sonography as a sequential screen for Down syndrome. Methods In this simulation study, published statistical parameters for first-trimester free β-human chorionic gonadotropin, pregnancy-associated plasma protein-A and nuchal translucency thickness, and second-trimester ultrasound markers (nuchal fold, hyperechoic bowel, short humerus, short femur, echogenic intracardiac focus, pyelectasis and major abnormality) were used to model the effectiveness of second-trimester genetic sonography combined with first-trimester screening. Results First-trimester combined screening alone resulted in a detection rate of 88.5% with a 4.2% false-positive rate. A follow-up genetic ultrasound examination in which only one sonographic marker was found and previous results were not taken into account would detect an additional 8% of Down syndrome cases for an additional false-positive rate of 13.2%. Using individual marker likelihood ratios to modify the first-trimester risk for screen-negative patients, genetic sonography detected an additional 6.1% of Down syndrome cases for an additional 1.2% false-positive rate, giving a total detection rate of 94.6% and a total false-positive rate of 5.4%. In a contingent protocol, in which genetic sonography would be performed only for patients with a first-trimester risk of between 1/300 and 1/2500, the detection rate was 4.8% and the false-positive rate was 0.7%, giving a total detection rate of 93.3% and a total false-positive rate of 4.9%. Conclusion Second-trimester genetic sonography, if used properly, can be an effective sequential screen following first-trimester Down syndrome screening. Further studies on the role of the genetic sonogram as a follow-up to first-trimester combined screening are warranted.
- Subjects
DOWN syndrome; MEDICAL screening; ULTRASONIC imaging; FIRST trimester of pregnancy; GENETICS
- Publication
Ultrasound in Obstetrics & Gynecology, 2007, Vol 29, Issue 6, p666
- ISSN
0960-7692
- Publication type
Article
- DOI
10.1002/uog.4029