Early ultrasound prediction of pregnancies affected by homozygous alpha-thalassaemia-1.
Homozygous alpha-thalassaemia-1 is conventionally diagnosed by invasive testing on all at-risk pregnancies. We evaluated the diagnostic efficacy of non-invasive abdominal ultrasonographic cardiothoracic ratio measurement in 62 pregnancies at 13-14 weeks and 75 pregnancies at 17-18 weeks. This performed better than placental thickness measurement. Using a cardiothoracic ratio cut-off level of > or = 0.5, 75 per cent of affected pregnancies were detected at 13-14 weeks and all cases were detected at 17-18 weeks. False-positive rates were 7 and 8 per cent, respectively. There was no false-positive diagnosis if the cardiothoracic ratio was > or = 0.53. With this approach, invasive procedures can be selectively performed and fewer pregnancies will be lost unnecessarily. The reduction in medical expenses is likely to be substantial.
Lam
Y H
YH
Department of Obstetrics and Gynaecology, University of Hong Kong, Tsan Yuk Hospital, Hong Kong.
Ghosh
A
A
Tang
M H
MH
Lee
C P
CP
Sin
S Y
SY
D005189:False Positive Reactions; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging; D005318:Fetal Heart / Q000000981:diagnostic imaging; D005865:Gestational Age; D006720:Homozygote; D006801:Humans; D010920:Placenta / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011247:Pregnancy; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013909:Thorax / Q000000981:diagnostic imaging / Q000196:embryology; D016216:Ultrasonography, Prenatal; D017085:alpha-Thalassemia / Q000000981:diagnostic imaging* / Q000235:genetics