Biparietal diameter/femur length ratio, cephalic index, and femur length measurements: not reliable screening techniques for Down syndrome.
Previous published reports have shown that fetuses affected with Down syndrome have normal biparietal diameter (BPD), high BPD-to-femur length ratio, and shorter femur length and occipitofrontal diameter. A retrospective comparison of the BPD, occipitofrontal diameter, cephalic index, femur length, and BPD/femur length ratio was made between 17 fetuses with Down syndrome diagnosed prenatally by second-trimester amniocentesis and 17 matched controls. The gestational age at sonographic evaluation in the two groups ranged from 15-23 weeks. The results of this study show no significant differences in the BPD, occipitofrontal diameter, cephalic index, femur length, and BPD/femur length ratio in the Down syndrome group when compared with controls. The sensitivity of BPD/femur length ratio as a screening technique for Down syndrome in this study was 18%, with a specificity of 94%. This sonographic method does not appear to be a useful screening parameter for Down syndrome.
Shah
Y G
YG
Department of Obstetrics and Gynecology, University of Rochester, Strong Memorial Hospital, New York.
Eckl
C J
CJ
Stinson
S K
SK
Woods
J R
JR
D000649:Amniocentesis; D002508:Cephalometry; D004314:Down Syndrome / Q000175:diagnosis / Q000196:embryology / Q000517:prevention & control*; D005269:Femur / Q000196:embryology; D005333:Fetus / Q000033:anatomy & histology*; D005624:Frontal Bone / Q000196:embryology; D005865:Gestational Age; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D009777:Occipital Bone / Q000196:embryology; D011237:Predictive Value of Tests; D011296:Prenatal Diagnosis / Q000379:methods*; D012044:Regression Analysis; D012189:Retrospective Studies; D014463:Ultrasonography