Kramer Michael S, Dahhou Mourad, Vallerand Danielle, Liston Robert, Joseph K S
Department of Pediatrics, Faculty of Medicine, McGill University, Montreal QC; Department of Epidemiology, Biostatistics and Occupational Health, Faculty of Medicine, McGill University, Montreal QC.
Department of Pediatrics, Faculty of Medicine, McGill University, Montreal QC.
J Obstet Gynaecol Can. 2011 Aug;33(8):810-819. doi: 10.1016/S1701-2163(16)34984-2.
To assess risk factors for postpartum hemorrhage (PPH) and the extent to which changes in those risk factors may explain the rising incidence of PPH recently reported from industrialized countries.
We carried out a hospital-based cohort study of 103 726 consecutive deliveries from January 1, 1978, to January 31, 2007, from the computerized medical records of a tertiary-care university maternity hospital in Montreal. We examined adjusted odds ratios for any PPH (estimated blood loss > 500 mL for vaginal deliveries, > 1000 mL for Caesarean sections), severe PPH (estimated blood loss ≥ 1500 mL), and PPH accompanied by blood transfusion and/or hysterectomy.
Major independent risk factors for PPH included primiparity, prior Caesarean section, placenta previa or low-lying placenta, marginal umbilical cord insertion in the placenta, transverse lie, labour induction and augmentation, uterine or cervical trauma at delivery, gestational age < 32 weeks, and birth weight ≥ 4500 g. An overall increase in rate of PPH over the study period (OR 1.029; 95% CI 1.024 to 1.034 per year) disappeared (OR 0.995; 95% CI 0.988 to 1.001 per year) after inclusion of maternal age, parity, prior Caesarean section, labour induction and augmentation, placenta previa or low-lying placenta, and abnormal placenta, with most of the reduction attributable to rises in previous Caesarean section and labour augmentation.
Labour induction, augmentation of labour, and prior Caesarean section are significantly associated with the risk of PPH, and their increase over the study period largely explains the observed rise in PPH.
评估产后出血（PPH）的危险因素，以及这些危险因素的变化在多大程度上可以解释近期工业化国家报道的PPH发病率上升情况。
我们基于蒙特利尔一家三级护理大学妇产医院1978年1月1日至2007年1月31日期间连续103726例分娩的计算机化医疗记录进行了一项医院队列研究。我们检查了任何PPH（阴道分娩估计失血量>500 mL，剖宫产>1000 mL）、严重PPH（估计失血量≥1500 mL）以及伴有输血和/或子宫切除术的PPH的校正比值比。
PPH的主要独立危险因素包括初产、既往剖宫产史、前置胎盘或低置胎盘、胎盘边缘性脐带插入、横位、引产和产程增加、分娩时子宫或宫颈创伤、孕周<32周以及出生体重≥4500 g。在纳入产妇年龄、产次、既往剖宫产史、引产和产程增加、前置胎盘或低置胎盘以及胎盘异常后，研究期间PPH发生率的总体上升（每年OR 1.029；95% CI 1.024至1.034）消失（每年OR 0.995；95% CI 0.988至1.001），大部分下降归因于既往剖宫产史和产程增加的上升。
引产、产程增加和既往剖宫产史与PPH风险显著相关，研究期间它们的增加在很大程度上解释了观察到的PPH上升情况。
