According to the findings of new research, pregnant women who live in areas with frequent heat waves and increased levels of air pollution face a higher risk of giving birth to a preterm baby, potentially signaling greater numbers of complications and health risks as climate change and air pollution worsen in the coming decades.
In a study published last week in the open access medical journal JAMA Network Open, researchers also indicate that air pollution and climate change may result in a higher risk of giving birth to a baby with low birth weight, or a baby who was stillborn.
Researchers conducted a review of 57 studies, including more than 32.7 million births, focusing on investigating prenatal exposure to fine particulate matter (PM) 2.5, ozone, heat and the link to preterm birth, low birth weight, and stillbirth.
The data indicated an association between exposure to heat, ozone, and fine particulate matter 2.5 and adverse pregnancy outcomes.
Particulate matter (PM) 2.5 is air pollution particles smaller than 2.5 micrometers, or 70 times smaller than the size of a single human hair. The particles are made of dirt and soot so small they are easily inhaled into the lungs and enter the bloodstream, leading to negative health effects including increased risk of cardiac arrest, cardiovascular disease and stroke.
In the study, air pollution and heat exposure related to climate change may be significantly associated with an increased risk to pregnancy outcomes in the United States.
Researchers concluded an association between exposure to PM 2.5 or ozone and increased risk of preterm birth was found in 79% of studies they reviewed.
Furthermore, the risk between climate change related air pollution and low birth weight was found in 85% of studies.
Nearly 90% of studies found a correlation between air heat exposure and negative pregnancy outcomes.
More so, positive associations were found across all U.S. geographic regions, not just in urban regions with increased populations.
Despite the increased association, researchers said it would be difficult to quantify the risk because each of the studies was conducted differently and focused on different outcomes. Instead, researchers aimed to determine if the studies had consistent findings regarding the associations between climate change, heat, and air pollution and negative birth outcomes.
The study findings indicate some women faced an especially high risk, including women with asthma and black women.
“This review suggests that increasingly common environmental exposures exacerbated by climate change are significantly associated with serious adverse pregnancy outcomes across the U.S.,” wrote study authors.
Reducing levels of air pollution are key to reducing the negative effects pregnant women face. Other studies have linked even short-term exposure to air pollution to increased risk of hospitalization, bloodstream infections and other complications.
Research published last year indicated exposure to air pollution may increase the risk of a woman having a “silent” miscarriage, or a miscarriage that is missed in the first trimester.