Lam Y H, Tang M H, Lee C P, Tse H Y
Department of Obstetrics and Gynecology, University of Hong Kong, Tsan Yuk Hospital, China.
Ultrasound Obstet Gynecol. 1999 Jan;13(1):48-51. doi: 10.1046/j.1469-0705.1999.13010048.x.
Fetuses affected by homozygous alpha-thalassemia-1 develop anemia as early as the first trimester. Our objective was to study hemodynamic indices in affected fetuses at 12-13 weeks of gestation to determine whether these would be useful in the prediction of anemia.
Prospective observational study.
Women referred before 14 weeks of gestation for the prenatal diagnosis of homozygous alpha-thalassemia-1.
Transabdominal and/or transvaginal Doppler sonography was performed to measure the flow velocities in the fetal ascending aorta and pulmonary artery at 12-13 weeks. The Doppler indices were compared between those that were subsequently confirmed to be affected by homozygous alpha-thalassemia-1 and those that were unaffected.
Between June 1997 and April 1998, 60 eligible women were recruited. Doppler examination was successful in 58 fetuses. Of these, 22 were subsequently confirmed to be affected by homozygous alpha-thalassemia-1. The diagnosis was made by chorionic villus sampling and DNA analysis in two affected fetuses and by cordocentesis and hemoglobin evaluation in 20 affected fetuses. Hemoglobin concentrations could be measured in ten fetuses and these ranged from 4 to 8 g/dl. The affected fetuses had significantly higher peak velocities at the pulmonary valve and ascending aorta and a larger inner diameter of the pulmonary valve than that in unaffected fetuses. The total cardiac output was increased by one-third in affected fetuses and was mainly due to an increase of the right-side cardiac output.
In the early stage of anemia, the fetus responds mainly by increasing its right-side cardiac output. However, there is extensive overlap of the values of cardiac output between the affected and the unaffected fetuses, precluding its use in the prediction of anemia.
受纯合子α地中海贫血-1影响的胎儿早在孕早期就会出现贫血。我们的目的是研究妊娠12至13周时受影响胎儿的血流动力学指标，以确定这些指标是否有助于预测贫血。
前瞻性观察研究。
妊娠14周前因纯合子α地中海贫血-1的产前诊断而转诊的妇女。
在12至13周时进行经腹和/或经阴道多普勒超声检查，测量胎儿升主动脉和肺动脉的血流速度。比较随后被证实受纯合子α地中海贫血-1影响的胎儿和未受影响胎儿的多普勒指标。
1997年6月至1998年4月，招募了60名符合条件的妇女。58例胎儿的多普勒检查成功。其中，22例随后被证实受纯合子α地中海贫血-1影响。2例受影响胎儿通过绒毛取样和DNA分析确诊，20例受影响胎儿通过脐血穿刺和血红蛋白评估确诊。10例胎儿可测量血红蛋白浓度，范围为4至8g/dl。受影响胎儿的肺动脉瓣和升主动脉峰值速度明显高于未受影响胎儿，肺动脉瓣内径也更大。受影响胎儿的心输出量增加了三分之一，主要是由于右侧心输出量增加。
在贫血早期，胎儿主要通过增加右侧心输出量做出反应。然而，受影响胎儿和未受影响胎儿的心输出量值有广泛重叠，因此无法用于预测贫血。
