According to the research, tackling maternal mortality may require looking beyond childbirth complications to the underlying health conditions women carry into pregnancy.
A new global study is reshaping understanding of the causes of maternal deaths, suggesting that anaemia, rather than excessive bleeding, may be a major underlying driver of mortality among pregnant women.
The findings, drawn from a study dubbed WOMAN-2 by the The Woman Trials, indicate that anaemia could be responsible for up to half of severe cases of postpartum haemorrhage (PPH) in sub-Saharan Africa and the South Asia region.
According to the research published on Wednesday and titled ‘The missing evidence: anaemia, postpartum, bleeding and maternal health,’ the research links the high prevalence of anaemia with increased risk of severe bleeding and death during childbirth.
The WOMAN Trials study is described as the first large epidemiological study of women giving birth with moderate or severe anaemia in sub-Saharan Africa and South Asia.
The study sampled at least 15,000 women with moderate and severe anaemia giving birth at hospitals in four countries, including Nigeria, Pakistan, Zambia, and Tanzania.
PPH, a severe bleeding after childbirth, has long been considered the leading cause of maternal deaths globally.
However, the latest research argues that this long-held assumption may be incomplete.
According to the new evidence, anaemia, a condition marked by low levels of haemoglobin in the blood significantly increases the risk of severe bleeding during and after childbirth.
Given its high prevalence in low and middle-income countries, experts estimate that anaemia may be driving a substantial proportion of both PPH cases and maternal deaths.
“In other words, our data suggest that anaemia rather than PPH is the leading cause of maternal death worldwide,” the report stated.
Nigeria continues to carry one of the highest maternal mortality burdens globally.
Estimates by the World Health Organisation (WHO) place the country’s maternal mortality ratio at 1,047 deaths per 100,000 live births, accounting for about a quarter of global maternal deaths.
Public health experts have repeatedly linked this burden to systemic challenges, including limited access to emergency obstetric care, shortages of skilled personnel, weak referral systems, and inadequate critical care infrastructure in many health facilities.
The findings also highlight gaps in global health policy.
In 2023, WHO released its roadmap to combat PPH for 2023-2030. However, the study results were not yet available at the time, meaning the role of anaemia was not fully incorporated into the strategy.
Experts say this omission has significant implications for maternal health interventions.
“Women with moderate and severe anaemia can develop shock and organ failure after only moderate bleeding; therefore, even the updated WHO definition of PPH fails to identify many women at high risk of death or near miss,” the report said.
“As part of our research, we set out to determine how accurate the diagnosis of PPH was in women with anaemia.
“The data showed that measuring blood loss alone was not accurate in identifying women at high risk of PPH death.”
Therefore, the study suggests that to reduce maternal deaths, a different approach, which includes diagnostic and prognostic criteria, including haemodynamic instability, maternal haemoglobin and other major risk factors, should be considered.
Beyond prevention, the findings also raise concerns about clinical practice.
The report warns that abnormal vital signs, such as changes in heart rate or blood pressure, in women with moderate or severe anaemia may not always indicate heavy bleeding.
In such cases, administering intravenous fluids, a common response to suspected haemorrhage, should be done with caution because fluid overload can cause breathing difficulties and is one of the leading causes of transfusion-related deaths.
“Women with severe anaemia were twice as likely to have a PPH diagnosis despite losing less than 500ml of blood.
“For a similar blood loss, they were more often transfused and with multiple units,” the report cautions.
The health experts urged that, as a preventive mechanism, all women should be screened for anaemia before and during pregnancy, and their haemoglobin levels should be known when giving birth.
They also recommended that haemoglobin levels be assessed at the time of delivery and that treatments such as tranexamic acid (TXA), which helps reduce bleeding, must be made widely available.
