(CNN) Anemia is emerging as a threat that can double the risk of death in pregnant women, according to a new study.
The research, published Tuesday in the British medical journal The Lancet Global Health, established a relationship between severe anemia and maternal death using one of the largest available datasets on pregnant women. It drew on information collected from 29 countries by the World Health Organization.
The goal was to explore whether there was an independent relationship between death and the condition of severe anemia, in which a person has a very low red blood cell count, said Jahnavi Daru, lead study author and a doctoral research fellow at Queen Mary University of London.
"There may be a relationship, but there were never enough numbers of outcomes [to establish it], because death as an outcome in pregnancy is very rare, said Daru"
Of the 312,281 pregnancies studied, 4,189 were identified as cases with severe anemia after accounting for other risk factors. Among those cases, there were 341 deaths. The study authors ran the numbers through two statistical models and found that both suggested a link between severe anemia and maternal death.
Previous studies could not attribute with confidence whether maternal death was caused by anemia or another medical condition. The results of the new study indicated that -- when all known contributing factors are controlled for -- the odds of maternal death are doubled in mothers with anemia.
"There were gaps in evidence in showing anemia actually has an outcome on maternal mortality and morbidity, although there were a lot of studies hinting at causality and temporality," said Dr. Rajmohan Panda, a senior specialist in health systems research and process evaluation at the George Institute for Global Health, who was not involved in the new research.
"The magnitude of this study, across different geographies, across different patients in different countries, is a step toward filling that gap."
Even though maternal health indicators have improved over the past few decades, more than 300,000 women died of complications of childbirth in 2015, according to the latest data from the WHO. Many of the health problems that lead to maternal death are treatable and preventable.
Anemia is one such problem, affecting about 500 million women. However, it has fallen off the radar for doctors, said Daru, who is also a clinician in obstetrics and gynecology. Pregnant women are more prone to anemia, as they need to provide nutrients for their developing babies in addition to themselves, yet the problem is not being readily addressed, she said.
One common form of anemia among pregnant women is iron-deficient anemia, which can be treated with iron supplements.
"We often think giving the iron tablets will solve the problem," Daru said. "Providing iron tablets has been happening for 50-odd years now, but this is still a problem."
What is needed, she said, is a broader approach that takes into account access to healthcare, education and other factors. "A lot of it comes down to how health care services are set up. Are women delivering in areas where there are trained attendants who can treat them? Are they even aware that anemia is a common problem?"
Women in developing countries bear the brunt of the mortality burden where access to quality health care or antenatal care is limited. Around the globe, 99% of deaths among pregnant women happen in developing countries, according to the WHO.
These include women in countries like Nigeria and India, which made up for a third of the world's total maternal deaths in 2015, with 58,000 and 45,000 deaths, respectively.
The study is also a message to policymakers that existing solutions aren't working. "It speaks to policymakers to strengthen and re-evaluate different anemia control programs," Panda said.