Analysis of secondary ultrasound markers in the first trimester before chorionic villus sampling.
OBJECTIVE
To evaluate detection and false-positive rates of the ultrasound markers-nasal bone (NB), ductus venosus (DV) flow and tricuspid regurgitation (TR)-during the first trimester in a population at high genetic risk, and to study the influence of a two-stage screening policy alter previous combined screening on the rate of invasive procedures.


METHODS
A total of 333 chorionic villus samples were obtained in singleton pregnancies. Before biopsy, the ultrasound markers-NB, DV, and TR-were assessed, although the findings were not used to recalculate the previously determined risk for Down syndrome.


RESULTS
Detection and false-positive rates for Down syndrome were 63.2% and 3.4% for NB, 65% and 3.1% for DV, and 50% and 2.1% for TR. All three markers were normal in 30% [84/277, 95% confidence interval (CI) 25%-36%] of chorionic villus sampling (CVS) cases performed for abnormal findings at the first trimester genetic screen, with 0% (0/20, 95% CI 0%-17%) false-negative rate for Down syndrome.


CONCLUSIONS
Assessment of secondary ultrasound markers is feasible in clinical practice and their use could reduce the number of unnecessary invasive procedures by 30%.
Molina García
Francisca S
FS
Fetal Medicine Unit, Obstetrics and Gynecology Service, Virgen de las Nieves University Hospital, Granada, Spain. fsoniamolina@gmail.com
Carrillo Badillo
María Paz
MP
Zaragoza García
Edgar A
EA
Fernández de Santos
Aránzazu Garrote
AG
Montoya Ventoso
Francisco
F
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis*; D015193:Chorionic Villi Sampling / Q000706:statistics & numerical data; D002869:Chromosome Aberrations / Q000706:statistics & numerical data; D004314:Down Syndrome / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005189:False Positive Reactions; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000502:physiology*; D013997:Time Factors; D016216:Ultrasonography, Prenatal / Q000592:standards* / Q000706:statistics & numerical data; D055815:Young Adult
D015415:Biomarkers