Biparietal diameter/femur length ratio and actual femur length/expected femur length ratio: a sonographic screening method for Down's syndrome.
Several ultrasonographic signs have been described in second-trimester Down's syndrome fetuses. Previously published reports have shown that fetuses affected with Down's syndrome have normal biparietal diameter (BPD), high BPD-to-femur length (FL) ratio, and low actual FL-to-expected FL ratio. A retrospective comparison of the BPD-to-FL ratio and actual FL-to-expected FL ratio was made between 3 fetuses with Down's syndrome diagnosed prenatally by second-trimester amniocentesis and 189 normal fetuses with gestational age varying from 13-25 weeks who were seen in the Ultrasound Unit of Department of Obstetrics & Gynaecology, Chulalongkorn Hospital between January 1, 1989 and May 31, 1990. The sensitivity of BPD-to-FL ratio and actual FL-to-expected FL ratio as a screening technique for Down's syndrome in this study was 66.7 and 100 per cent, with a specificity of 93.4 and 89.2 per cent respectively. These sonographic parameters appear to be a useful screening method for Down's syndrome.
Sukcharoen
N
N
Department of Obstetrics & Gynaecology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Tannirandorn
Y
Y
Suwajanakorn
S
S
Paosawadi
S
S
D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000196:embryology; D005315:Fetal Diseases / Q000175:diagnosis*; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012044:Regression Analysis; D012886:Skull / Q000000981:diagnostic imaging / Q000196:embryology; D016216:Ultrasonography, Prenatal