Extreme Heat Waves and Increasing Blackouts Threaten Pregnant Women

Extreme heat is hard on the body. It can cause everything from confusion to seizures, let alone serious discomfort. Add a blackout to an ongoing heat wave — so no a/c — and everything gets worse.

A study out this week in the journal Environmental Science & Technology looked at the health effects when electrical grids fail during sustained heatwaves. The findings are alarming: Patients would overwhelm hospitals in the cities of Atlanta, Phoenix, and Detroit. In Phoenix, the authors write, more than half the city’s residents would end up in the emergency room with heat-related illnesses, and, in all three cities, deaths would more than double.

Among those affected, one group in particular is likely to suffer disproportionately in this kind of crisis: pregnant women. With the earth’s rising temperature causing ever more extreme heat waves, pregnant women face higher chances of early labor, stillbirth, or low birthweight — especially in the late weeks of pregnancy. The risk is even greater for women of color. Black women specifically have twice the probability for these negative outcomes than white women.

And blackouts have been on the rise: Between 2011 and 2021 there were 84 percent more weather-related blackouts than in the previous decade, with grids overwhelmed by intense electrical use during summer months, according to Climate Central, a nonprofit research group of scientists.

The warming climate and an inability to cool down “could have major implications for child health,” said another study, this one in BMJ, a journal published by the British Medical Association. Multiple researchers have found that preterm births go up 16 percent during heat waves.

“Really what we think is that with heat exposure, dehydration is really the root cause,” epidemiologist Rupa Basu told NPR. “Dehydration causes hormonal changes, which gives a message to a mother to deliver an infant. The blood flow in the uterus decreases.”

Results of a 2010 study by Basu and her colleagues found that in California, for every extra 10 degrees, the risk of preterm birth went up by 8 percent. The BMJ research found that “even apparently minor decrements in birth weight could have a major impact on public health as exposure to high temperatures is common and escalating.”

One problem that can be addressed is that doctors have not been discussing the risks of high heat on their pregnant patients. The American College of Obstetricians and Gynecologists said in 2021 that it “recognizes that climate change is an urgent women’s health concern as well as a major public health challenge,” and recommended that doctors counsel patients on environmental hazards like extreme heat during prenatal care visits.

“Special consideration must be given to protecting pregnant people and newborns, in light of their increased vulnerability to climate-change–related harm,” doctors wrote in a 2022 article in The New England Journal of Medicine.

The authors stressed that “actions to reduce these effects should be initiated now.” They pointed to making preparedness and response planning a priority for public health agencies and health system. As an example of early intervention, the doctors wrote that “ensuring that all pregnant patients — particularly those living in areas at high risk for extreme weather events — have access to their electronic medical records could support the transfer of prenatal care to a new location in the event of disruption.”

They also warned that more research is needed “on interventions that could alleviate the effects of climate change on these groups.”