Detection Rates for Aneuploidy by First-Trimester and Sequential Screening.
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%.


CONCLUSIONS
First-trimester and sequential screening are sensitive and specific for the broad range of karyotype abnormalities seen in the population.


METHODS
II.
California 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.
Rebecca J
RJ
Baer
Monica C
MC
Flessel
Laura L
LL
Jelliffe-Pawlowski
Sara
S
Goldman
Louanne
L
Hudgins
Andrew D
AD
Hull
Mary E
ME
Norton
Robert J
RJ
Currier
D000328:Adult; D000782:Aneuploidy; D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome / Q000175:diagnosis; D005260:Female; D006801:Humans; D062145:Maternal Serum Screening Tests / Q000706:statistics & numerical data*; D048208:Nuchal Translucency Measurement / Q000706:statistics & numerical data*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood; D012189:Retrospective Studies; D014314:Trisomy / Q000175:diagnosis; D000073842:Trisomy 18 Syndrome