A recent study published in The Lancet, involving a large cohort of women from Pakistan, Nigeria, Tanzania, and Zambia has shed light on the relationship between maternal anaemia and the risk of postpartum haemorrhage (PPH). The study, which examined anaemia as a continuous variable, found a strong association between low prebirth haemoglobin concentration and an increased likelihood of PPH. These findings are significant, given that PPH is a leading cause of maternal mortality worldwide, particularly in low-income and middle-income countries.
According to global statistics, approximately 500 million women of reproductive age are anaemic, with 20 million of them experiencing severe anaemia. The highest prevalence of anaemia is observed in western and central Africa and south Asia, where approximately half of women of reproductive age suffer from this condition. Poor access to a healthy diet, untreated heavy menstrual bleeding, and exposure to chronic infectious diseases such as HIV, malaria, tuberculosis, or intestinal parasites are believed to be the primary causes of anaemia in these regions.
Anaemia has significant consequences for both maternal and child health. In adults, it can lead to reduced work capacity, while in children, it can result in poor cognitive and motor development. Severe anaemia during pregnancy also poses a heightened risk of maternal and infant death. Furthermore, PPH, characterized by excessive bleeding within 24 hours after childbirth, causes approximately 70,000 maternal deaths annually worldwide. Low-income and middle-income countries bear the majority of this burden.
The study in question utilized a large dataset and examined the association between prebirth haemoglobin levels and PPH risk. Unlike previous studies that recorded anaemia as a categorical variable, this study used true haemoglobin concentrations as a continuous measure. The researchers found a consistent association between low prebirth haemoglobin concentration and increased risk of PPH, regardless of the definition of PPH used. Furthermore, women with severe anaemia had a significantly higher risk of death or near-miss events.
The study’s strengths include its large sample size, accurate measurement of haemoglobin levels, minimal loss to follow-up, and comprehensive control of potential confounding factors. However, the authors acknowledge some limitations, such as possible measurement errors and inaccuracies in estimating blood loss. Additionally, the study focused on women with moderate or severe anaemia, preventing an investigation of the association between haemoglobin levels and PPH risk in women with mild anaemia.
Given the significant prevalence of anaemia and its strong association with PPH risk, efforts to correct anaemia before delivery should be prioritized. The findings from this study reinforce the importance of addressing anaemia as a preventive measure to reduce the incidence of PPH and improve maternal outcomes. Future research, including ongoing clinical trials, will further explore the potential interactions between haemoglobin levels and interventions such as tranexamic acid in preventing PPH.
The recent cohort study provides compelling evidence of the relationship between maternal anaemia and the risk of postpartum haemorrhage. By examining haemoglobin levels as a continuous variable, the study establishes a clear dose-response relationship, supporting the notion of a causal association. The study’s findings highlight the urgent need for interventions targeting anaemia in women of reproductive age, with the goal of reducing the incidence of postpartum haemorrhage and improving maternal and child health outcomes worldwide.