Guerra F, Naranjo E, Campos G
Instituto de Obstetricia y Ginecología y de Fisiología, Unviersidad Austral de Chile, Valdivia.
Rev Chil Obstet Ginecol. 1994;59(1):22-6.
To evaluate the changes of blood flow velocities of the uterine and external iliac arteries, we studied a total of 15 normal full term pregnant, which were in the active phase of labor. The mean maternal age was 21.6 +/- 5.2 years (X +/- SD), the mean parity was 0.6 +/- 0.5, and the mean gestational age was 39.2 +/- 1.1 weeks. All patients had normal deliveries, the newborn weight was 3440 +/- 621 g, and the apgar score was 8.6 +/- 1.6 and 9.0 +/- 0.7 at 1 and 5 min, respectively. In the uterine artery, the systolic/diastolic ratio and the resistance index increased significantly from 1.83 +/- 0.25 to 4.24 +/- 1.55 (p < 0.05) and from 0.46 +/- 0.05 to 0.74 +/- 0.08 (p < 0.01), respectively from the relaxation phase to the contraction phase. In all 15 patients the external iliac artery showed a reverse diastolic flow during uterine relaxation, whereas only 2 of the 14 patients showed this reverse flow during uterine contraction (p < 0.01). Furthermore, the flow velocity was modified with maternal hyperventilation. Finally, we conclude that uterine contraction induced profound changes in the blood flow velocities in the uterine and external iliac arteries. We proposed that these changes could be explained by uterine muscular contractions causing the blood flow to be shunted to areas of less resistance.
为评估子宫动脉和髂外动脉血流速度的变化，我们共研究了15例足月正常妊娠且处于产程活跃期的孕妇。孕妇平均年龄为21.6±5.2岁（X±SD），平均产次为0.6±0.5，平均孕周为39.2±1.1周。所有患者均顺产，新生儿体重为3440±621g，1分钟和5分钟时的阿氏评分分别为8.6±1.6和9.0±0.7。在子宫动脉中，从舒张期到收缩期，收缩压/舒张压比值和阻力指数分别从1.83±0.25显著增加至4.24±1.55（p<0.05）和从0.46±0.05显著增加至0.74±0.08（p<0.01）。在所有15例患者中，子宫舒张期髂外动脉出现反向舒张期血流，而14例患者中只有2例在子宫收缩期出现这种反向血流（p<0.01）。此外，母体过度通气会改变血流速度。最后，我们得出结论，子宫收缩引起子宫动脉和髂外动脉血流速度的深刻变化。我们认为这些变化可以用子宫肌肉收缩导致血流分流到阻力较小的区域来解释。
