Identification of fetuses with hemoglobin Bart's disease using middle cerebral artery peak systolic velocity

Objectives To determine the sensitivity and specificity of middle cerebral artery peak systolic velocity (MCA‐PSV) in mid‐pregnancy for the identification of homozygous α‐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. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.