Identifying Regional Variation in the Prevalence of Postpartum Haemorrhage: A Systematic Review and Meta-Analysis

ObjectiveTo provide regional estimates of the prevalence of maternal haemorrhage and explore the effect of methodological differences between studies on any observed regional variation.
MethodsWe conducted a systematic review of the prevalence of maternal haemorrhage, defined as blood loss greater than or equal to 1) 500 ml or 2) 1000 ml in the antepartum, intrapartum or postpartum period. We obtained regional estimates of the prevalence of maternal and severe maternal haemorrhage by conducting meta-analyses and used meta-regression to explore potential sources of between-study heterogeneity.
FindingsNo studies reported the prevalence of antepartum haemorrhage (APH) according to our definitions. The prevalence of postpartum haemorrhage (PPH) (blood loss ≥500 ml) ranged from 7.2% in Oceania to 25.7% in Africa. The prevalence of severe PPH (blood loss ≥1000 ml) was highest in Africa at 5.1% and lowest in Asia at 1.9%. There was strong evidence of between-study heterogeneity in the prevalence of PPH and severe PPH in most regions. Meta-regression analyses suggested that region and method of measurement of blood loss influenced prevalence estimates for both PPH and severe PPH. The regional patterns changed after adjusting for the other predictors of PPH indicating that, compared with European women, Asian women have a lower prevalence of PPH.
ConclusionsWe found evidence that Asian women have a very low prevalence of PPH compared with women in Europe. However, more reliable estimates will only be obtained with the standardisation of the measurement of PPH so that the data from different regions are comparable.

研究目的：本研究旨在估算孕产妇出血（maternal haemorrhage）的区域患病率，并探讨不同研究间的方法学差异对观测到的区域差异的影响。
研究方法：我们针对孕产妇出血的患病率开展了系统综述，将其定义为产前、产时或产后时期失血量≥1）500ml或2）1000ml。通过荟萃分析获取孕产妇出血及重症孕产妇出血的区域患病率估算值，并采用Meta回归探索研究间异质性的潜在来源。
研究结果：暂无研究按照本研究的定义报告产前出血（antepartum haemorrhage, APH）的患病率。产后出血（postpartum haemorrhage, PPH，失血量≥500ml）的患病率范围为大洋洲的7.2%至非洲的25.7%。重症产后出血（失血量≥1000ml）的患病率以非洲最高（5.1%），亚洲最低（1.9%）。多数区域的PPH及重症PPH患病率均存在显著的研究间异质性。Meta回归分析显示，失血量测量的区域与方法，会对PPH及重症PPH的患病率估算产生影响。在校正PPH的其他预测因素后，区域分布模式发生改变，结果提示相较于欧洲女性，亚洲女性的PPH患病率更低。
研究结论：本研究发现，与欧洲女性相比，亚洲女性的PPH患病率极低。然而，唯有实现产后出血测量方法的标准化，使不同区域的数据具备可比性，方能获得更可靠的患病率估算结果。