Veille J C, Morton M J, Burry K J
Am J Obstet Gynecol. 1985 Oct 1;153(3):261-3. doi: 10.1016/s0002-9378(85)80109-5.
Multiple pregnancy places increased demands on the maternal circulation. Maternal left ventricular size and performance were measured with M-mode echocardiography in women with twin pregnancy in the second and third trimesters, and the findings were compared to those in normal singleton pregnancies. As expected, cardiac output was greater during twin than during singleton pregnancy; however, end-diastolic ventricular dimension was not. Output was increased in twin pregnancy during the second and third trimesters by heart rate and also during the third trimester by stroke volume. Increased stroke volume was effected by increased shortening, thus strongly suggesting increased contractility. Increased maternal heart rate and contractility during multiple gestations suggest that cardiovascular reserve is reduced.
多胎妊娠对母体循环提出了更高的要求。采用M型超声心动图测量了孕中期和孕晚期双胎妊娠女性的母体左心室大小和功能，并将结果与正常单胎妊娠女性的结果进行了比较。正如预期的那样，双胎妊娠时的心输出量高于单胎妊娠；然而，舒张末期心室尺寸并非如此。双胎妊娠在孕中期和孕晚期心输出量增加是由于心率增加，在孕晚期还由于每搏输出量增加。每搏输出量增加是由缩短增加所致，因此强烈提示收缩力增加。多胎妊娠时母体心率和收缩力增加表明心血管储备降低。
