Heat Wave Increases Life-Threatening Complications in Labor for Pregnant Individuals, Especially Those Exposed to Prolonged High Temperatures

New research, titled "Analysis of Heat Exposure During Pregnancy and Severe Maternal Morbidity" published in the Journal of the American Medical Association, links extreme heat exposure during pregnancy to a higher risk of life-threatening complications during childbirth.

This study adds to existing evidence, differentiating between long-term heat exposure and isolated heatwaves. Ashley Ward, the director of Duke University's Heat Policy Innovation Hub, underscores the significance of distinguishing between chronic heat exposure and acute heatwave events in understanding the risks to pregnant individuals.

Prolonged Heat Exposure Linked to Elevated Maternal Morbidity

Using data sourced from Kaiser Permanente Southern California pertaining to pregnancies that occurred between 2007 and 2018, the research team conducted an analysis of daily maximum temperatures to assess the degree of heat exposure experienced during each trimester.

They identified noteworthy associations between both short- and long-term heat exposure, typically categorized as lasting 30 days or more during pregnancy, and instances of severe maternal morbidity.

The Centers for Disease Control and Prevention (CDC) defines severe maternal morbidity as encompassing 21 unanticipated complications arising during labor or delivery that nearly result in maternal mortality, including conditions such as cardiac arrest, eclampsia, heart failure, sepsis, and the need for ventilation.

Notably, the study was unable to incorporate data related to blood transfusions during delivery, a common indicator of severe maternal morbidity, due to limitations in data granularity.

The research revealed a 27% increase in these risks associated with high exposure to extreme heat throughout pregnancy or during the third trimester. Exposure to heat wave during the final gestational week was also linked to an elevated risk of life-threatening delivery complications.

Notably, this study coincides with a summer that saw record-breaking global heat, with Phoenix experiencing a record of 31 consecutive days with temperatures exceeding 110 degrees Fahrenheit. Several other cities across the United States, including Texas, Louisiana, and California, also reported their own unprecedented heat streaks.

In essence, the study utilized extensive pregnancy and temperature data to establish a clear correlation between heat exposure and severe maternal morbidity during childbirth, with implications heightened by record-breaking heatwaves observed globally.

The study found no significant racial or ethnic disparities but revealed that individuals with lower educational levels had an elevated risk of severe maternal morbidity associated with heat exposure.

This highlights the necessity for healthcare professionals and public health experts to implement focused interventions aimed at educating and assisting pregnant individuals with lower educational backgrounds, as they may not fully comprehend how extreme heat can affect pregnancy outcomes.

Furthermore, the research established a connection between heat exposure and cardiovascular events during pregnancy and labor. This is concerning given that cardiovascular conditions have emerged as a leading cause of pregnancy-related deaths in the United States, despite medical advancements, indicating a worsening crisis in maternal health.

Quantifying the Effects of Climate Change on Pregnant Individuals and Babies

A separate study in Africa revealed a 1.15-fold increase in the risk of adverse birth outcomes, like preterm birth, during heatwaves. However, a crucial research gap exists in quantifying the absolute number of additional climate change-related adverse outcomes.

These statistics could help comprehend climate change's impact on maternal and child health, potentially eroding progress made in areas like childhood vaccination.

The research estimated that climate change could contribute to 7,000 to 11,000 child deaths annually in Africa due to heat exposure. Without substantial carbon emission reductions, heat-related child mortality in Africa could exceed 38,000 per year by 2049, necessitating urgent emission reduction measures.

Additionally, a study in Johannesburg found an 80% increase in severe hypertensive disorders in early pregnancy when temperatures surpassed 23°C, underscoring pregnant individuals' heightened vulnerability to rising temperatures and associated health risks.

Check out more news and information on Climate Change in Science Times.