Combs C A, Laros R K
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco.
Obstet Gynecol. 1991 Jun;77(6):863-7.
Although retained placenta is a major cause of postpartum hemorrhage, there is no general agreement regarding when manual placental extraction is indicated to prevent hemorrhage. We sought to determine the following: 1) what duration of the third stage of labor is abnormal, 2) what duration is associated with complications, and 3) what antecedent conditions are associated with prolonged third stage. We studied 12,979 consecutive, singleton vaginal deliveries over an 11-year period. Third-stage duration had a log-normal distribution, with a geometric mean of 6.8 minutes, a median of 6 minutes, and an interquartile range of 4-10 minutes. A third stage of 30 minutes or longer occurred in 3.3% of the deliveries. The incidence of postpartum hemorrhage, transfusion, and D&C remained constant in third stages less than 30 minutes, then rose progressively, reaching a plateau at 75 minutes. The increase in these complications after 30 minutes was observed with both spontaneously delivered and manually extracted placentas. In a logistic regression analysis, factors significantly associated with prolonged third stage included: preterm delivery (odds ratio 3.81), delivery in a labor bed (odds ratio 2.17), preeclampsia (odds ratio 1.76), augmented labor (odds ratio 1.47), and nulliparity (odds ratio 1.45). Because there was no increase in hemorrhage until the third stage exceeded 30 minutes, we suggest that in the absence of bleeding, manual placental extraction is not indicated until 30 minutes have elapsed.
尽管胎盘滞留是产后出血的主要原因，但对于何时进行人工胎盘剥离以预防出血尚无普遍共识。我们试图确定以下几点：1）第三产程的异常时长是多少，2）与并发症相关的时长是多少，3）与第三产程延长相关的前置情况有哪些。我们研究了11年间连续的12979例单胎阴道分娩病例。第三产程时长呈对数正态分布，几何平均数为6.8分钟，中位数为6分钟，四分位间距为4 - 10分钟。3.3%的分娩第三产程时长达到30分钟或更长。产后出血、输血及刮宫的发生率在第三产程少于30分钟时保持稳定，之后逐渐上升，在75分钟时达到平台期。在自然分娩和人工剥离胎盘的情况下，30分钟后这些并发症均有所增加。在逻辑回归分析中，与第三产程延长显著相关的因素包括：早产（比值比3.81）、在产床上分娩（比值比2.17）、先兆子痫（比值比1.76）、引产（比值比1.47）及初产（比值比1.45）。由于直到第三产程超过30分钟出血才增加，我们建议在无出血的情况下，30分钟内无需进行人工胎盘剥离。
