Ear length in second-trimester aneuploid fetuses.
OBJECTIVE
To test the hypothesis that small ears have diagnostic value in detecting second-trimester aneuploid fetuses by ultrasound.


METHODS
We prospectively studied 452 patients with singleton pregnancies undergoing ultrasound examination for genetic amniocentesis at 14-25 weeks and an additional 30 singleton pregnancies at 20-25 weeks with a negative anomaly screen. Standard fetal biometry measurements were obtained, including ear length (from helix to end of lobe).


RESULTS
Of these patients, 424 (88%) had ear measurements obtained, and a nomogram for ear length by gestational age was compiled. The relationship between ear length and gestational age was linear across the second trimester (r = 0.84, P < .001). Fourteen fetuses had aneuploidy by amniocentesis, of whom ten had ear lengths at or below the tenth percentile. The sensitivity was 71% and the specificity 92% (377 of 410). Positive and negative predictive values were 23% (ten of 43) and 99% (377 of 381), respectively.


CONCLUSIONS
Fetal ear length may be useful in identifying aneuploid fetuses sonographically during the second trimester.
Lettieri
L
L
Department of Obstetrics and Gynecology, University of Connecticut Health Center, Farmington.
Rodis
J F
JF
Vintzileos
A M
AM
Feeney
L
L
Ciarleglio
L
L
Craffey
A
A
D000782:Aneuploidy; D002869:Chromosome Aberrations / Q000175:diagnosis; D025063:Chromosome Disorders; D004423:Ear / Q000000981:diagnostic imaging / Q000196:embryology*; D005260:Female; D005333:Fetus / Q000033:anatomy & histology; D005865:Gestational Age; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal