Heart Research Center, Oregon Health & Science University, 3303 SW Bond Ave, CH15H, Portland, OR 97239-3098, USA.
Curr Vasc Pharmacol. 2013 Sep;11(5):748-57. doi: 10.2174/1570161111311050012.
Although blood flow in the placental vasculature is governed by the same physiological forces of shear, pressure and resistance as in other organs, it is also uniquely specialized on the maternal and fetal sides. At the materno-fetal interface, the independent uteroplacental and umbilicoplacental circulations must coordinate sufficiently to supply the fetus with the nutrients and substrates it needs to grow and develop. Uterine arterial flow must increase dramatically to accommodate the growing fetus. Recent evidence delineates the hormonal and endothelial mechanisms by which maternal vessels dilate and remodel during pregnancy. The umbilical circulation is established de novo during embryonic development but blood does not flow through the placenta until late in the first trimester. The umbilical circulation operates in the interest of maintaining fetal oxygenation over the course of pregnancy, and is affected differently by mechanical and chemical regulators of vascular tone compared to other organs. The processes that match placental vascular growth and fetal tissue growth are not understood, but studies of compromised pregnancies provide clues. The subtle changes that cause the failure of the normally regulated vascular processes during pregnancy have not been thoroughly identified. Likewise, practical and effective therapeutic strategies to reverse detrimental placental perfusion patterns have yet to be investigated.
虽然胎盘血管中的血流受到与其他器官相同的生理力（剪切力、压力和阻力）的控制，但它在母体和胎儿两侧也具有独特的专门功能。在母体-胎儿界面，独立的子宫胎盘和脐胎盘循环必须充分协调，为胎儿提供生长和发育所需的营养物质和底物。子宫动脉血流必须大幅增加以适应不断成长的胎儿。最近的证据描述了激素和内皮细胞机制，这些机制在怀孕期间使母体血管扩张和重塑。脐循环在胚胎发育过程中是全新建立的，但直到妊娠早期末血液才流经胎盘。脐循环的运作是为了在整个妊娠过程中维持胎儿的氧合，并且与其他器官相比，它受到血管张力的机械和化学调节剂的不同影响。与胎盘血管生长和胎儿组织生长相匹配的过程尚不清楚，但对有问题妊娠的研究提供了线索。导致妊娠期间正常调节的血管过程失败的微妙变化尚未得到彻底确定。同样，尚未研究出实用有效的治疗策略来逆转有害的胎盘灌注模式。
