Indication-specific accuracy of second-trimester genetic ultrasonography for the detection of trisomy 21
Objective: The object of this study was to determine whether there are any clinically significant indication-specific variations in the accuracy of second-trimester genetic ultrasonography and to provide a risk adjustment for fetal trisomy 21 according to the results of genetic ultrasonography. Stud...
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Published in | American journal of obstetrics and gynecology Vol. 181; no. 5; pp. 1045 - 1048 |
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Main Authors | , , , , |
Format | Journal Article Conference Proceeding |
Language | English |
Published |
Philadelphia, PA
Mosby, Inc
01.11.1999
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Objective: The object of this study was to determine whether there are any clinically significant indication-specific variations in the accuracy of second-trimester genetic ultrasonography and to provide a risk adjustment for fetal trisomy 21 according to the results of genetic ultrasonography.
Study Design: From November 1, 1992, to September 30, 1998, a second-trimester genetic sonogram was offered to all pregnant women who were at an increased risk for fetal trisomy 21 (≥1:274) because of either advanced maternal age (≥35 years) or abnormal serum biochemical profile or both of these. Outcome information included the results of genetic amniocentesis if performed and the results of pediatric assessment and follow-up after birth. In determining diagnostic accuracy of the genetic sonogram the presence of ≥1 abnormal ultrasonographic marker was considered an abnormal test result.
Results: A total of 1835 fetuses with known outcomes underwent genetic ultrasonography between 15 and 24 weeks’ gestation; of these 1792 had normal results, 34 had trisomy 21, and 9 had other chromosomal abnormalities. The likelihood of fetal trisomy 21 was reduced by 80% after a normal result of genetic ultrasonography. The overall sensitivity, specificity, and positive and negative predictive values of genetic ultrasonography for the detection of trisomy 21 were 82%, 91%, 15%, and 99.6%, respectively. There were no significant indication-specific variations in the accuracy of second-trimester ultrasonography. The sensitivity for the detection of fetal trisomy 21 ranged from 80% among women with advanced maternal age to 100% among women with both an abnormal biochemical profile and advanced maternal age.
Conclusions: The likelihood of fetal trisomy 21 risk was reduced 80% after a normal result of genetic ultrasonography. In addition there were no significant indication-specific variations in the detection rate of genetic ultrasonography. (Am J Obstet Gynecol 1999;181:1045-8.) |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0002-9378 1097-6868 |
DOI: | 10.1016/S0002-9378(99)70078-5 |