Objective: To evaluate the efficacy of using fetal heart size measurements derived from axial echocardiography to predict homozygous α-thalassemia-1.
Design: Prospective diagnostic study.
Setting: The carrier rate of α-thalassemia-1 (-/αα) in China's Guangxi Zhuang Autonomous Region is approximately 15%. If both parents are carriers, the risk of homozygous α-thalassemia-1 in one pregnancy is 25%.
Patients: Singleton mid-pregnancies at risk of homozygous α-thalassemia-1 were enrolled.
Outcome measures: Fetal heart measurements, including heart diameter (HD), heart length (HL), heart circumference (HC), and heart area (HA), were measured. The z-scores for these heart parameters were then calculated separately based on previously constructed z-score models. Finally, the accuracy of these predictive variables was analyzed and compared to that achieved by cardiothoracic ratio (CTR) using a receiver operating characteristic (ROC) curves analysis.
Results: A total of 214 singleton pregnancies were recruited. The discriminatory power of HA and HD z-scores was better (z-test P< .01) while that of HC and HL z-scores was comparable to (z-test P>.05) that of CTR. HD combined with HA z-scores had the highest sensitivity (100%), and the specificity of HD and/or HA z-scores was 100%.
Conclusion: Fetal heart size measurements are novel, effective and noninvasive predictors of homozygosity for α-thalassemia-1 in mid-pregnancy. The discriminatory power of HD and HA z-scores was better than while that of HC and HL z-scores was comparable to that of CTR. Further investigation is needed to understand the effectiveness of these predictors.
Keywords: fetal echocardiography; heart size; homozygous α-thalassemia-1; midpregnancy; prenatal diagnosis; z-scores.
© 2018 Wiley Periodicals, Inc.