Related Experiment Video
Updated: Apr 4, 2026
Semiconductor Sequencing for Preimplantation Genetic Testing for Aneuploidy
Published on: August 25, 2019
Detection Rates for Aneuploidy by First-Trimester and Sequential Screening
Rebecca J Baer1, Monica C Flessel, Laura L Jelliffe-Pawlowski
1California Department of Public Health, Genetic Disease Screening Program, Richmond, the Department of Pediatrics, University of California, San Diego, La Jolla, California; the Departments of Epidemiology and Biostatistics and Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, the Division of Medical Genetics, Stanford University, Stanford, California, and Maternal Fetal Care and Genetics, University of California, San Diego, San Diego, California.
Objective:
To estimate detection rates for aneuploidy by first-trimester and sequential screening.
Methods:
The study included women with singleton pregnancies who participated in the California Prenatal Screening Program with estimated delivery dates from August 2009 to December 2012 who had first- or first- and second-trimester (sequential) screening. Detection rates were measured for target (trisomies 21 and 18) and other aneuploidies identified from the California Chromosome Defect Registry.
Results:
Of 452,901 women screened, 17,435 (3.8%) were screen-positive for Down syndrome only; 433 (0.1%) for trisomy 18 only; 1,689 (0.4%) for both Down syndrome and trisomy 18; and 2,947 (0.7%) for neural tube defects, Smith-Lemli-Opitz syndrome, or for multiple conditions. The detection rates were Down syndrome-92.9% (95% confidence interval [CI] 91.4-94.2); trisomy 18-93.2% (95% CI 90.5-95.9); trisomy 13-80.4% (95% CI 73.9-86.9); 45,X-80.1% (95% CI 73.9-86.3), and triploidy-91.0% (95% CI 84.2-97.9). Overall, the detection rate for chromosome abnormalities was 81.6% (95% CI 80.0-83.1) at an overall false-positive rate of 4.5%.
Conclusion:
First-trimester and sequential screening are sensitive and specific for the broad range of karyotype abnormalities seen in the population.
Level Of Evidence:
II.
