目的：超声观察正常中晚期妊娠胎儿心排血量及其分布情况的变化。方法行超声心动图检查的孕中晚期单胎正常孕妇250例，根据孕周分为五组：20～24周（50例），24＋1～28周（55例），28＋1～32周（65例）、32＋1～36周（45例），36＋1～40周（35例）。测定肺动脉瓣、主动脉峡部最大内径和动脉导管各部位血流频谱，包括E峰、A峰及E／A ；计算不同孕周胎儿左、右心室排血量、主动脉峡部排血量及动脉导管排血量。结果正常中晚期胎儿肺动脉瓣、主动脉峡部最大内径、动脉导管的血流频谱（E峰和E／A）随孕周的增加而增加（P＜0．05），而A峰值随孕周的增加无明显变化（P＞0．05）。正常中晚期胎儿左、右心室心排血量、主动脉峡部排血量和动脉导管排血量随孕周的增加而增加（ P＜0．05），且与孕周呈正相关（ r＝0.362、0.378、0.369和0.352，P＜0．05）。结论分析不同孕周正常中晚期胎儿血流频谱及心排血量分布情况可为胎儿早期血流量异常变化引起的后期形态学改变提供指导，对早期筛查心功能异常胎儿具有重要的指导价值。%Objective To investigate the changes of cardiac output and distribution by ultrasonography in the fetuses during middle and late pregnancy .Methods A total of 250 normal fetuses underwent ultrasonography was divided into five groups of A (20‐24 pregnancy weeks ,50 cases) ,B(24+1‐28 pregnancy weeks ,55 cases) ,C(28+1‐32 pregnancy weeks ,65 cases) ,D(32+1‐36 pregnancy weeks ,45 cases) and E(36+1‐40 pregnancy weeks ,35 cases) .The blood flow spectrums (E peak ,A peak and E/A ) of fetal pulmonary valve ,maximal diameter of the aortic isthmus ,artery ductus were measured .The cardiac output of left ,right ventricle ,aortic isthmus and artery ductus were calculated .Results The blood flow spectrums (including E peak and E/A) of pulmonary valve , maximal diameter of aortic isthmus ,and artery ductus were increased as the pregnancy week increased (P<0 .05) ,while A peak was not significantly changed (P>0 .05) .The cardiac output of left and right ventricles ,aortic isthmus ,and artery ductus were increased as the pregnancy week increased (P<0 .05) ,which were positively correlated with pregnancy weeks ( r=0.362 ,0.378 ,0.369 and 0.352 ,P<0 .05) .Conclusion The analysis of normal fetal blood flow spectrums and cardiac output distribution in different pregnancy weeks by ultrasonography can provide a guidance of the late morphological changes caused by early fetal blood flow changes ,which has an important value for early screening abnormal fetal heart function .
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