News: New report suggests link between severe maternal morbidity and extreme heat
A new study conducted by a group of international researchers suggests that exposure to extreme heat during pregnancy is associated with a higher risk of severe maternal morbidity (SMM), according to MedPage Today.
The journal article, published in JAMA Network Open, examined 403,602 pregnancies between January 1, 2008 and December 31, 2018, at Kaiser Permanente, a large integrated healthcare organization in Southern California.
As defined by the CDC, cases of SMM include the “unexpected outcomes of labor and delivery that result in significant short or long-term consequences to a woman’s health.”
The journal article delineated previous research suggesting an upward trend in these phenomena over the past decade or so: for example, it was noted that the rates of SMM in 2014 were three times greater than those even 20 years ago.
However, the authors argued that the prevailing causative explanations found in the previous literature—such as “improvements in case identification and changes in maternal characteristics”—could not fully explain the trends.
The researchers examined pregnancies occurring within a gestational stage of 20 to 47 weeks. Moreover, they defined the temperature categories of moderate, high, and extreme heat as the “daily maximum temperatures exceeding the 75th, 90th, and 95th percentiles of the times series data from May through September 2007 to 2018 in Southern California, respectively.”
In an interview with MedPage Today, one of the co-authors, Anqi Jiao, a PhD candidate at the University of California Irvine, said that not only were extreme heats associated with an uptick in SMM, but that there was a “critical exposure window” during the third trimester.
According to the researchers, other risk factors—such as adolescent pregnancy older age, and lower education levels/socioeconomic status—further heightened the risk for SMM.
Editor’s note: To read the MedPage Today article, click here. To read the CDC definition of severe maternal morbidity, click here. To read the JAMA Network Open article, click here.