Prenatal ultrasound monitoring of homozygous α 0 -thalassemia-induced fetal anemia

• Published in: Best practice & research. Clinical obstetrics & gynaecology Vol. 39; p. 53
• Main Authors: Lee, Helena H L, Mak, Annisa S L, Poon, C F, Leung, K Y
• Format: Journal Article
• Language: English
• Published: Netherlands 01.02.2017
• Subjects: alpha-Thalassemia - diagnostic imaging; Anemia - diagnostic imaging; Blood Flow Velocity; Cardiomegaly - diagnostic imaging; Female; Fetal Diseases - diagnostic imaging; Fetal Heart - diagnostic imaging; Humans; Middle Cerebral Artery - diagnostic imaging; Nuchal Translucency Measurement; Placenta - diagnostic imaging; Pregnancy; Pregnancy Trimester, First; Pregnancy Trimester, Second; Thorax - diagnostic imaging; Ultrasonography, Doppler; Ultrasonography, Prenatal; α-thalassemia; prenatal ultrasonography; cardiomegaly; prenatal diagnosis; Hb-Bart's disease; middle cerebral artery

A noninvasive approach by serial ultrasound examination at 12-15, 18, and 30 weeks of gestation can be used to exclude homozygous α -thalassemia-induced fetal anemia. At 12-15 weeks of gestation, the predictive values for the fetal cardio-thoracic ratio were better than that for the placental thickness. At 16-20 weeks of gestation, measuring middle cerebral artery peak systolic velocity is associated with a low false-positive rate. However, the false-positive rate of this noninvasive approach can be about 3%, requiring an invasive test to confirm the diagnosis. A false-negative may result in a delay in diagnosis. The success of this noninvasive approach depends on an accurate measurement of the fetal cardiothoracic ratio which can be improved by adequate training and subsequent quality control. Currently, there is a lack of data reporting the performance of a noninvasive approach before 12 weeks of gestation.