A study conducted by the University of California at Irvine has found a significant connection between maternal heat exposure during pregnancy and a higher likelihood of severe maternal health problems. This findings could have important implications for public health strategies and interventions.
Extended heat exposure in third trimester linked to SMM
In a JAMA Network Open paper titled “Analysis of Heat Exposure During Pregnancy and Severe Maternal Morbidity,” researchers investigated the link between maternal heat exposure and severe maternal morbidity (SMM).
The study conducted on 403,602 pregnancies, with an average age of 30.3 years, sourced from data from Kaiser Permanente Southern California, revealed 3,446 cases of SMM (0.9%) over a decade (2008 to 2018). The research assessed prolonged heat exposure during pregnancy using heat day proportions, classified as moderate, high, and extreme. It found notable links between extended heat exposure, especially in the third trimester, and SMM.
The study examined the impact of short-term heat wave exposure in the final week of pregnancy using nine distinct definitions of heat waves, each defined by temperature thresholds and durations. The results revealed significant associations with heat wave exposure, with stronger links observed as heat wave severity increased.
SMM rates on the rise in the last two decades
The Centers for Disease Control and Prevention describes Severe Maternal Morbidity (SMM) to include unexpected labor and delivery complications with significant health consequences for women. Recent indicators show a consistent rise in SMM cases.
The study notes that SMM rates in 2014 were nearly three times higher than two decades ago. Despite suggested explanations, they do not completely account for this increasing trend.
The study links the season of conception to severe maternal morbidity (SMM). It reveals that pregnancies starting in the cold season (November to April) make mothers more susceptible to heat exposure and its connection to SMM compared to pregnancies starting in the warm season (May to October). This implies that the timing of conception affecting pregnancy stages during hotter months can impact the link between heat exposure and SMM.
