Varga I, Rigó J, Somos P, Joó J G, Nagy B
1st Department of Obstetrics and Gynecology of Semmelweis University Medical School, Budapest, Hungary.
J Matern Fetal Med. 2000 Mar-Apr;9(2):97-104. doi: 10.1002/(SICI)1520-6661(200003/04)9:2<97::AID-MFM2>3.0.CO;2-3.
The aim of the study was to examine the temporal relations between the parameters of the maternal hemodynamics and homeostasis in different phases of pregnancy and the postpartum period.
Eleven healthy pregnant women were involved in the study. The value of the peripheric vasodilatation was measured by the ratio I/A of the maternal sphygmogram (I: incisure point, A: amplitude of the carotid pressure curve). The change of the cardiac output was determined by the ejection angle composed from maternal carotid sphygmogram and its first electrical derivate (dP/dT). The glomerular filtration rate (GFR) was measured with the in vitro radiofluorescent method.
The primary peripheral vasodilatation and GFR increase occur early in the first trimester of a normal pregnancy, start to decrease at the end of the third trimester, and return to the normal value in the postpartum period. The increase of GFR precedes the increase of cardiac output. The cardiac output increases progressively from the first trimester and starts to decrease in the third trimester of a normal pregnancy. The extracellular volume increases at the beginning of first trimester progressively until the end of pregnancy and returns to the normal value in the postpartum period.
The increase of GFR and the cardiac output during pregnancy are contributed to volume-establishment and to the cessation of the special "underfilled" condition of the maternal circulation in the normal pregnancy. We suppose that the maximal increase of GFR precedes the maximal increase of the cardiac output because the GFR increase is caused by maximal renal vasodilatation. The increase of cardiac output is caused in the first trimester by the shunt effect of the enhanced renal blood flow of maternal kidneys, and in the second and third trimester by the shunt effect of the feto-placental unit and the shunt effect of the maternal kidneys.
本研究旨在探讨孕期不同阶段及产后母体血液动力学参数与内环境稳态之间的时间关系。
11名健康孕妇参与了本研究。外周血管舒张值通过母体脉搏图的I/A比值来测量（I：切迹点，A：颈动脉压力曲线的振幅）。心输出量的变化通过由母体颈动脉脉搏图及其一阶电导数（dP/dT）组成的射血角度来确定。肾小球滤过率（GFR）采用体外放射性荧光法测量。
正常妊娠早期外周血管舒张和GFR开始增加，孕晚期开始下降，产后恢复至正常水平。GFR的增加先于心输出量的增加。心输出量从孕早期开始逐渐增加，在正常妊娠的孕晚期开始下降。细胞外液量在孕早期开始逐渐增加，直至妊娠末期，产后恢复至正常水平。
孕期GFR和心输出量的增加有助于建立血容量，并消除正常妊娠时母体循环中特殊的“充盈不足”状态。我们推测GFR的最大增加先于心输出量的最大增加，因为GFR的增加是由最大程度的肾血管舒张引起的。心输出量在孕早期因母体肾脏肾血流量增加的分流作用而增加，在孕中期和晚期则因胎儿-胎盘单位的分流作用和母体肾脏的分流作用而增加。
