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Causes of and risk factors for postpartum haemorrhage: a systematic review and meta-analysis

I. Yunas, Md Asiful Islam, K. N. Sindhu, A. Devall, M. Podesek, Sayeda Sadia Alam, Shoumik Kundu, Kristie-Marie Mammoliti et al.

The Lancet, 2025

847 participants · 76 citations

Abstract

BACKGROUND

An understanding of the causes of postpartum haemorrhage is needed to provide appropriate treatment and services. Knowledge of the risk factors for postpartum haemorrhage can help address modifiable risk factors. We did a systematic review and meta-analysis to identify and quantify the various causes and risk factors for postpartum haemorrhage.

METHODS

In this systematic review and meta-analysis, we did a systematic literature search in MEDLINE, Embase, Web of Science, Cochrane Library, and Google Scholar for cohort studies of postpartum haemorrhage from Jan 1, 1960, to Nov 30, 2024 without language restrictions. At least two authors independently undertook study selection, data extraction, and quality assessment. Population-based cohort studies available in English were eligible. Rates of postpartum haemorrhage causes as well as crude and adjusted odds ratios (ORs) for risk factors were pooled using a random-effects model. Risk factors were classified as having weak, moderate, or strong association based on the pooled ORs: weak (OR >1 to 1·5), moderate (OR >1·5 to 2), and strong (OR >2). This study is registered with PROSPERO, CRD42023479686.

FINDINGS

We synthesised data from 327 studies, including 847 413 451 women with no restriction on age, race, or ethnicity. Most studies were of high methodological quality. The pooled rates of the five commonly reported causes of postpartum haemorrhage were uterine atony (70·6% [95% CI 63·9-77·3]; n=834 707 women, 14…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 847 participants or records.

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