Sonographic Markers of Fetal α‐Thalassemia Major

α‐Thalassemia prevails in Southeast Asia, where α‐thalassemia major is a lethal type. Sonography is a helpful and cost‐effective screening tool for detecting α‐thalassemia major fetuses. The cardiothoracic ratio, placental thickness, and middle cerebral artery peak systolic velocity are most used in clinical practice. These sensitive markers are helpful for evaluation of the hemodynamic status and cardiovascular function of the affected fetuses. They can predict fetal α‐thalassemia major and assess the efficacy of treatment noninvasively; therefore, the medical costs as well as the possibility of fetal loss caused by invasive procedures can be reduced. Other potentially useful sonographic markers need further studies, although previous preliminary research suggests their usefulness. This article will review those sonographic markers.