Identification of fetuses with hemoglobin Bart's disease using middle cerebral artery peak systolic velocity.
OBJECTIVE
To determine the sensitivity and specificity of middle cerebral artery peak systolic velocity (MCA-PSV) in mid-pregnancy for the identification of homozygous alpha-thalassemia-1 (hemoglobin (Hb) Bart's disease) in fetuses at risk of the disease.


METHODS
A total of 88 pregnancies (91 fetuses) at risk of Hb Bart's disease and undergoing MCA-PSV measurement before cordocentesis at 18-22 weeks of gestation were recruited into the study. Definitive diagnosis was made using the gold standard technique of Hb typing by high-performance liquid chromatography.


RESULTS
The mean +/- SD age of the 88 pregnant women recruited into the study was 28.3 +/- 5.7 years, the gestational age was 18.8 +/- 1.1 weeks and the incidence of Hb Bart's disease was 22% (20 fetuses). Using MCA-PSV above 1.5 multiples of the median as a cut-off point, the sensitivity of MCA-PSV for detecting affected fetuses was 85% (17/20 cases), with a specificity of 100%, and positive and negative predictive values of 100% and 95.9% respectively. Three of 20 fetuses with Hb Bart's disease had normal MCA-PSV.


CONCLUSIONS
MCA-PSV assessment in mid-pregnancy is a useful method for identifying Hb Bart's disease with high sensitivity and specificity among fetuses at risk, and may allow avoidance of unnecessary cordocentesis in some cases.
Srisupundit
K
K
Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Piyamongkol
W
W
Tongsong
T
T
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D017218:Cordocentesis; D005260:Female; D005315:Fetal Diseases / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005865:Gestational Age; D006455:Hemoglobins, Abnormal; D006801:Humans; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000196:embryology / Q000503:physiopathology*; D011247:Pregnancy; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*; D017085:alpha-Thalassemia / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology
D006455:Hemoglobins, Abnormal; C030448:hemoglobin Bart's