Dawood M Y
Department of Obstetrics, Gynecology and Reproductive Sciences, University of Texas Medical School at Houston 77030, USA.
Adv Exp Med Biol. 1995;395:585-94.
New information and understanding about the physiology of oxytocin (OT) have provided the bases of novel and rational approaches to the induction and augmentation of labor with OT. Based on a half-life of 8-10 min and time to steady state of 20 min, the interval between intravenous OT dose increments during uterine stimulation should be 20-30 min. Feto-maternal blood plasma gradients of OT concentration in spontaneous labor at term indicate a feto-uterine flow of 2-4mU OT/min. Labor can be successfully induced in most women with such physiological doses (2-6 mU/min) of OT given intravenously. Direct and indirect evidence show that OT is released in pulses with the frequency and/or amplitude of the pulses increasing with or during spontaneous labor. Further OT interaction with its receptor renders it occupied and temporarily unavailable. We have therefore employed these observations to induce and augment labor with pulsatile intravenous administration of OT. In a prospective randomized study of 106 patients undergoing labor induction with pulsatile versus continuous administration of OT, the total dose, the average dose/min, and the peak or highest dose required/min were significantly reduced with pulsatile OT compared with continuous OT. These significant differences remained when controlled for parity, Bishop's score of cervical ripeness, and the number of days for induction. Similarly in a prospective randomized study on augmentation of labor by intravenous OT, we found the dose of OT for successful augmentation was significantly reduced with pulsatile OT compared with continuous OT. Thus, pulsatile OT not only is safe and requires less OT for uterine stimulation, but also constitutes a more physiological basis for uterine stimulation.
关于催产素（OT）生理学的新信息和新认识为采用OT引产和加强宫缩提供了新颖且合理的方法基础。基于其8 - 10分钟的半衰期和20分钟达到稳态的时间，子宫刺激期间静脉注射OT剂量增加的间隔应为20 - 30分钟。足月自然分娩时母胎血浆OT浓度梯度表明胎儿 - 子宫的OT流量为2 - 4mU/分钟。大多数女性静脉注射这种生理剂量（2 - 6mU/分钟）的OT能够成功引产。直接和间接证据表明，OT以脉冲形式释放，脉冲频率和/或幅度在自然分娩期间或随着自然分娩而增加。OT与其受体的进一步相互作用使其被占据并暂时无法发挥作用。因此，我们利用这些观察结果通过静脉脉冲给药OT来引产和加强宫缩。在一项对106例接受OT脉冲给药与持续给药引产患者的前瞻性随机研究中，与持续OT相比，脉冲OT给药时的总剂量、平均每分钟剂量以及所需的峰值或最高每分钟剂量均显著降低。在对产妇经产情况、宫颈成熟度的Bishop评分以及引产天数进行控制后，这些显著差异依然存在。同样，在一项关于静脉注射OT加强宫缩的前瞻性随机研究中，我们发现与持续OT相比，脉冲OT成功加强宫缩所需的OT剂量显著降低。因此，脉冲OT不仅安全且子宫刺激所需的OT量更少，而且为子宫刺激构成了更符合生理的基础。
