Fetal anaemia as a cause of fetal injury: diagnosis and management

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.

Fetal magnetic resonance imaging of acquired and developmental brain anomalies

During the last decade, increasing interest in magnetic resonance imaging has emerged for the evaluation of fetal abnormalities detected on ultrasound. The advent of single-shot rapid acquisition sequences has greatly facilitated our ability to obtain detailed imaging information of the fetal brain. To date, fetal magnetic resonance imaging has shown to have an important role in the investigation of cerebral abnormalities suspected by sonography, and in the detection of subtle brain anomalies associated with high-risk pregnancies. Magnetic resonance imaging has proved to be a useful adjunct to sonography during the prenatal period of development, especially for the detection of acquired disorders.

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 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.