Effectiveness of ultrasound algorithm in prenatal diagnosis of hemoglobin Bart's disease among pregnancies at risk

Abstract

Objective: To evaluate the effectiveness of ultrasound algorithm in diagnosis of fetal Hb Bart's disease among pregnancies at risk.

Methods: Pregnancies at risk underwent ultrasound for the first time at 12-14 weeks of gestation and serial ultrasound every 2-4 weeks until 24 weeks to identify pre-hydropic signs. The invasive procedure was omitted in case of no pre-hydropic signs.

Results: A total of 237 fetuses were recruited, including 53 affected and 184 unaffected fetuses. The algorithm has a sensitivity of 100% in the detection of fetal Hb Bart's disease with a false positive rate of 10.9%. Of the affected group, the mean gestational age at the time of diagnosis was 15.5 ± 2.6 week. 30.8% of all pregnancies at risk underwent invasive procedures. The algorithm had a 70% reduction in the rate of invasive procedures among pregnancies at risk without missing the affected cases.

Conclusions: The algorithm is highly effective in the early detection of fetal Hb Bart's disease with a detection rate of 100%, and invasive diagnosis can be avoided in about 70% of cases. Thus, this algorithm should be used as a guideline for prenatal diagnosis of fetal Hb Bart's disease, especially in geographical areas of high prevalence.

Keywords: Alpha-thalassemia; cardiothoracic ratio (CTR); hemoglobin Bart's disease; middle cerebral artery - peak systolic velocity (MCA-PSV); ultrasound.