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Epidemiology of postpartum haemorrhage: a systematic review

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Postpartum haemorrhage (PPH) is an important cause of maternal mortality. We conducted a systematic review of the prevalence of PPH with the objective of evaluating its magnitude both globally and in different regions and settings: global figures, as well as regional, country and provincial variations, are likely to exist but are currently unknown. We used prespecified criteria to select databases, recorded the database characteristics and assessed their methodological quality. After establishing PPH (≥500 mL blood loss) and severe PPH (SSPH) (≥1000 mL blood loss) as main outcomes, we found 120 datasets (involving a total of 3,815,034 women) that reported PPH and 70 datasets (505,379 women) that reported SPPH in the primary analysis. The prevalence of PPH and SPPH is approximately 6% and 1.86% of all deliveries, respectively, with a wide variation across regions of the world. The figures we obtained give a rough estimate of the prevalence of PPH and suggest the existence of some variations. For a reliable picture of PPH worldwide – its magnitude, distribution and consequences – a global survey tackling this condition is necessary.

Introduction

Bleeding after childbirth (postpartum haemorrhage, PPH) is an important cause of maternal mortality. It accounts for nearly one-quarter of all maternal deaths worldwide, with an estimated of 125,000 deaths per year.1 As there are about 125 million births annually in the developing world2, the risk of maternal death from PPH is approximately 1 in 1000 deliveries. In the United Kingdom, the risk of maternal death from PPH is about 1 in 100,000 births.3

PPH is defined as blood loss from the genital tract of 500 mL or more in the first 24 hours after the delivery of the baby. Severe postpartum haemorrhage (SPPH) is defined as blood loss from the genital tract of 1000 mL or more in the first 24 hours after the delivery of the baby. PPH is also associated with morbidity including blood transfusion, renal failure, coagulation deficiencies and long-term morbidity, such as anaemia. Hysterectomy and other surgical procedures to reduce blood flow to the uterus and their subsequent consequences in fertility have to be considered as consequences of PPH, although it is difficult to quantify their burden.

Common causes of PPH include failure of the uterus to contract adequately after birth (atonic PPH), which accounts for 90% of PPH in most countries; trauma to the genital tract (traumatic PPH), which accounts for about 7% of PPH; and bleeding due to retention of placental tissue and failure in the coagulation system, which accounts for the remaining 3%. Atonic PPH is the most prevalent of these conditions and the leading cause of maternal death, particularly in low- and middle-income countries.

Regional, country and provincial variations on the abovementioned global figures are likely to exist but are not currently known. There is therefore a need to establish the magnitude and the regional distribution of PPH around the world so as to adequately inform reproductive health policies and programmes. We conducted a systematic review of the prevalence of PPH with the objective of evaluating the magnitude of the problem globally and in different regions and settings.

Section snippets

Methods

We used the World Health Organization (WHO) Systematic Review of Maternal Mortality and Morbidity Project Protocol4, 5 as a template. We used the same criteria for screening, identification and selection of studies and added an additional criterion (blood loss numerically quantified as more than 500 mL and more than 1000 mL, measured either objectively or subjectively) to all potentially eligible papers. The review covers the period 1997–2006.

Results

The WHO database includes 121 reports published between 1997 and 2002. Of these, 93 had an incorrect definition of PPH and four had not specified the period of study. Thus, we selected only 24 reports because these were the only ones numerically to quantify the blood loss (e.g. blood loss ≥500 mL for PPH, blood loss ≥1000 mL for SPPH). These 24 studies provided a total of 100 datasets (Figure 1).

For the period 2003–2006, full texts of 166 reports were further assessed. The final number of reports

Discussion

From our datasets, the prevalence of PPH is approximately 6% of all deliveries. However, those studies that measured blood loss objectively, as opposed to subjectively, showed a higher prevalence. This is also observed in RCTs, where it would be expected that the blood loss was measured carefully. PPH prevalence for rural populations is higher than for the urban settings but the number of datasets for both populations are rather small. The prevalence of PPH in vaginal deliveries is higher than

Acknowledgements

This study was supported by United States Agency for International Development (USAID) and the UNDP/UNFPA/World Bank Special Programme for Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, WHO, Geneva 27, CH-1211, Switzerland.

We thank Mrs Mary Ellen Stanton for her support to the review and Dr Lale Sale for her contribution to the WHO search that supported part of the study.

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