According to the Health Effects Institute, more than three billion people around the world cook on open fires using solid fuels — or biomass — such as wood, dung, charcoal and agricultural waste. These types of stoves are not commonly used for cooking in the United States. But in some countries, exposure to the resulting household air pollution has been found to be associated with several adverse health outcomes — including low birthweight in offspring of pregnant women, which remains a major public health challenge, particularly in low- and middle-income countries.

In an effort to learn more about household air pollution’s effect on low birthweight, a group of researchers led by Emory University (Thomas Clasen), Colorado State University (Jennifer Peel) and Johns Hopkins University (William Checkley), collaborated and performed an international study — the Household Air Pollution Intervention Network (HAPIN) trial, involving 3,200 pregnant women who cook primarily with biomass stoves, in Guatemala, India, Peru and Rwanda. The group described findings from their study on October 10 in the New England Journal of Medicine.

A team of researchers from national and international institutions, including William Checkley, M.D., Ph.D., an adult pulmonologist at Johns Hopkins Medicine and Director of the Center for Global Non-Communicable Disease Research and Training and Eric McCollum, M.D., a pediatric pulmonologist at Johns Hopkins Children’s Center, provided a randomized group of pregnant women, ranging in ages 18 to 35 years old, with an alternative to a biomass stove — a liquified petroleum gas stove. Researchers measured 24-hour exposure to fine particulate matter, black carbon and carbon monoxide twice during pregnancy, as well as their baby’s birthweight within 24 hours of birth.

The study found no significant difference in birthweight of newborns of pregnant women who used both types of stoves. However, findings indicate the use of petroleum gas stoves substantially reduced the amount of household air pollution, making it one of the largest studies to achieve clean indoor air through a multi-component household air-pollution intervention. However, the investigators say further research is necessary to understand the study’s findings. The group is continuing other aspects of the HAPIN trial, including studying the effects household air pollution has on stunting growth of children, severe pneumonia in infants, and blood pressure in women.