Pregnant women with anaemia are twice as likely to die during or shortly after pregnancy compared to those without the condition, according to a major international study led by Queen Mary University of London of over 300,000 women across 29 countries.
The research, funded by Barts Charity and the Human Reproduction Programme, suggests that prevention and treatment of maternal anaemia must remain a global public health and research priority.
Anaemia, which is characterised by a lack of healthy red blood cells, affects 32m pregnant women worldwide, and up to half of all pregnant women in low and middle-income countries (LMICs). Women in LMICs are at increased risk of anaemia due to higher rates of dietary iron deficiency, inherited blood disorders, nutrient deficiencies and infections such as malaria, HIV and hookworm.
Lead author Dr Jahnavi Daru from Queen Mary University of London said: “anaemia in pregnancy is one of the most common medical problems pregnant women encounter both in low and high-income countries. We’ve now shown that if a woman develops severe anaemia at any point in her pregnancy or in the seven days after delivery, she is at a higher risk of dying, making urgent treatment even more important.
“Anaemia is a readily treatable condition but the existing approaches so far have not been able to tackle the problem. Clinicians, policy makers and healthcare professionals should now focus their attention on preventing anaemia, using a multifaceted approach, not just hoping that iron tablets will solve the problem.”
The study, which is the largest of its kind, looked at World Health Organisation data on 312,281 pregnancies in 29 countries* across Latin America, Africa, Western Pacific, Eastern Mediterranean and South East Asia. Of these, 4,189 women had severe anaemia (a blood count of less than 70 grams per litre of blood) and were matched with 8,218 women without severe anaemia.
Previous studies had suggested that anaemia was strongly associated with death, but that this was due to other clinical reasons, and not anaemia directly. This analysis is the first to take into account factors that influence the development of anaemia in pregnancy (blood loss or malaria infection) which may have been skewing the results of previous studies.
The study results showed that, when all known contributing factors are controlled for, the odds of maternal death are doubled in mothers with severe anaemia.
The relationship was seen in different geographical areas and using different statistical approaches, which suggests an independent relationship between severe anaemia and maternal death does exist.
Francesca Gliubich, director of grants at Barts Charity, said: “Barts Charity are proud of having contributed to this work. The research will help to shape health policies worldwide by providing scientific evidence of the importance of prevention and treatment of maternal anaemia, ultimately saving lives and avoiding preventable deaths.”
Strategies for the prevention and treatment of maternal anaemia include providing oral iron tablets for pregnant women, food fortification with iron, improving access to antenatal care in remote areas, hookworm treatment and access to transfusion services.
The study has limitations including its observational nature meaning that a direct causal relationship between severe anaemia and maternal death cannot be proven, because other factors may come into play.
The study included authors from CIBER Epidemiology and Public Health (Spain), World Health Organisation, National Centre for Child Health and Development (Japan), Sao Paulo Federal University (Brazil), Fortis Memorial Research Institute (India), Ministry of Health (Sri Lanka), Khon Kaen University (Thailand) and University of Tsukuba (Japan).
*The countries included in the study were Afghanistan, Angola, Argentina, Brazil, Cambodia, China, Democratic Republic of the Congo, Ecuador, India, Japan, Jordan, Kenya, Lebanon, Mexico, Mongolia, Nepal, Nicaragua, Niger, Nigeria, Pakistan, Palestine, Paraguay, Peru, Philippines, Qatar, Sri Lanka, Thailand, Uganda, Vietnam.
Background: Anaemia affects as many as half of all pregnant women in low-income and middle-income countries, but the burden of disease and associated maternal mortality are not robustly quantified. We aimed to assess the association between severe anaemia and maternal death with data from the WHO Multicountry Survey on maternal and newborn health.
Methods: We used multilevel and propensity score regression analyses to establish the relation between severe anaemia and maternal death in 359 health facilities in 29 countries across Latin America, Africa, the Western Pacific, eastern Mediterranean, and southeast Asia. Severe anaemia was defined as antenatal or postnatal haemoglobin concentrations of less than 70 g/L in a blood sample obtained before death. Maternal death was defined as death any time after admission until the seventh day post partum or discharge. In regression analyses, we adjusted for post-partum haemorrhage, general anaesthesia, admission to intensive care, sepsis, pre-eclampsia or eclampsia, thrombocytopenia, shock, massive transfusion, severe oliguria, failure to form clots, and severe acidosis as confounding variables. These variables were used to develop the propensity score.
Findings: 312 281 women admitted in labour or with ectopic pregnancies were included in the adjusted multilevel logistic analysis, and 12 470 were included in the propensity score regression analysis. The adjusted odds ratio for maternal death in women with severe anaemia compared with those without severe anaemia was 2·36 (95% CI 1·60–3·48). In the propensity score analysis, severe anaemia was also associated with maternal death (adjusted odds ratio 1·86 [95% CI 1·39–2·49]).
Interpretation: Prevention and treatment of anaemia during pregnancy and post partum should remain a global public health and research priority.
Jahnavi Daru, Javier Zamora, Borja M Fernández-Félix, Joshua Vogel, Olufemi T Oladapo, Naho Morisaki, Özge Tunçalp, Maria Regina Torloni, Suneeta Mittal, Kapila Jayaratne, Pisake Lumbiganon, Ganchimeg Togoobaatar, Shakila Thangaratinam, Khalid S Khan