Heat Waves Increases Rates of Preterm Births, Leads To Poorer Health For Babies

A recent study reveals that heatwaves raise the number of preterm births, which can have an adverse effect on the long-term health of the babies and result in worse health outcomes.

Heat Waves Effects On Pregnancy

The climate crisis is causing extreme heat events to occur more frequently, persist longer, and intensify more. Record-breaking temperatures were seen last year. In July 2023, the world experienced four consecutive days of the hottest day ever recorded.

Furthermore, the Center for Disease Control and Prevention (CDC) states that pregnant women are among the most susceptible to heat stress and are more likely to suffer from heat exhaustion and stroke. Their unborn children may suffer as a result of this.

Lyndsey Darrow, an epidemiologist at the University of Nevada, and her colleagues examined national birth records from 1993 to 2017 in the 50 most populous metropolitan regions of the United States, a nation where heatwaves are happening twice as frequently as they did in the 1960s and have increased in intensity by 24%.

The researchers discovered that daily rates of early-term birth (37 to less than 39 weeks) and preterm birth (between 28 and less than 37 weeks' gestation) increased slightly when local temperatures rose, especially among lower socioeconomic groups. However, these findings did not apply to rural areas not included in the data.

After heat waves, mothers who are black, Hispanic, or from lower socioeconomic backgrounds are especially vulnerable to giving birth early.

The researchers observed that pre-existing medical issues, the ability to avoid physically demanding jobs in hot weather, and access to housing with dependable air conditioning may have also altered pregnant people's unique risk of heat.

Not just short heat waves have an effect on pregnancy outcomes. According to the study, extended periods of above-average temperatures might also have negative effects.

Long-Term Health Impact

Preterm birth is the primary cause of infant mortality and is linked to a range of long-term respiratory and neurological consequences for the child. Dehydration, decreased blood flow, and the release of labor-inducing chemicals can all cause early labor and premature contractions.

Researchers who were not part of the most recent study also note that there is a lack of research on the long-term health impacts of premature birth caused by intense heat.

"By failing to include these implications of preterm and early-term births in public health assessments, we vastly underestimate the effects of heat on population health," said Caleb Dresser, an emergency medicine physician at the Harvard T. H. Chan School of Public Health in Boston.

An increasing body of research indicates that pregnant patients require specific guidance on how to manage heat stress. According to a 2022 study, there is still little and conflicting advice against heat exposure for expectant mothers.

"There should be extra counseling in clinics and general materials about ways to protect from dehydration and heat stress during times of extreme heat, which is getting more and more common," said Nathaniel DeNicola, an OB-GYN specialist who authored the 2022 report on air pollution and preterm births.