Are second-trimester minor sonographic markers for Down syndrome useful in patients who have undergone first-trimester combined screening?
OBJECTIVE
We sought to determine efficacy of minor markers for detection of Down syndrome (DS) in a population prescreened with first-trimester combined screening (FTS).


METHODS
FTS was modified using established likelihood ratios to generate a new composite risk (NCR).


RESULTS
Of 3845 women, 390 had ≥1 marker. There were 10/3845 cases of DS; 3 were among patients with low-risk FTS (n = 3727). In 55 patients, NCR adjusted the risk from low to high without increasing detection rate. NCR did not modify risk to allow for detection of the 3 DS among patients with low-risk FTS even though 2 of these fetuses had 1 minor marker each. There were 7 DS among patients with high-risk FTS (n = 118). Use of NCR increased positive predictive value from 7/118 (5.1%) to 7/53 (13.2%).


CONCLUSIONS
Screening for minor markers is useful in patients with high-risk FTS. It is of questionable benefit in patients with low-risk FTS.
Sood
Monica
M
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, North Shore-Long Island Jewish Health System, Manhasset, NY 11030, USA. msood@nshs.edu
Rochelson
Burton
B
Krantz
David
D
Ravens
Rachel
R
Tam Tam
Hima
H
Vohra
Nidhi
N
Lewis
Dawnette
D
Ray
Bidisha
B
D000328:Adult; D015331:Cohort Studies; D004314:Down Syndrome / Q000175:diagnosis*; D004452:Echocardiography; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging; D007422:Intestines / Q000000981:diagnostic imaging; D007682:Kidney Pelvis / Q000000981:diagnostic imaging; D016013:Likelihood Functions; D008403:Mass Screening; D048208:Nuchal Translucency Measurement; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D012189:Retrospective Studies