Pregnant women are facing two colliding health crises this summer: the ongoing coronavirus pandemic and extreme heat. The two challenges together are putting some pregnancies at greater risk, health experts say.
A growing body of scientific research links exposure to extreme heat during a woman’s pregnancy to increased risk of delivering early, having a baby with a low birth weight, and even infant mortality.
That’s a problem because this summer is proving to be a hot one. This July, large swaths of the US, especially in the South, have experienced brutal heat waves. And this past June has tied as the third-hottest on record globally, according to the National Oceanic and Atmospheric Administration. As the world warms due to climate change, the threat of extreme heat is only expected to get worse.
Black and brown women and women with low incomes are far more vulnerable to suffer health consequences from heat. According to one study of more than 2 million babies born in California between 1999 and 2013, which looked at the link between temperature exposure and low birth weight, Black women were the most at risk of delivering small babies. Black women are already at much greater risk of dying from pregnancy-related causes.
But local health officials aren’t getting the word out. A BuzzFeed News review of the online heat and safety guidelines provided by local health and emergency response departments for 25 of the most-populated US cities found only two — Chicago and Philadelphia — identified pregnant people as among those especially vulnerable to heat.
While still very little is known about the risks the coronavirus poses to pregnant women, the CDC updated its guidance this summer to warn that “pregnant people might be at an increased risk for severe illness.” So far, at least 14,000 pregnant women in the US have tested positive for the coronavirus, more than 3,000 of them were hospitalized, and at least 35 of them have died. And a preliminary analysis of this data found pregnant Latina and Black women were more likely to get severely ill from COVID-19.
Extreme heat and the pandemic together may put pregnant women in a bind: Do you stay outdoors, where the virus is less likely to spread, but risk being exposed to heat? Or seek relief in potentially crowded indoor spaces blasting cool air, such as grocery stores, malls, and libraries?
“That’s really a big problem,” said Rupa Basu, an epidemiologist at the California Environmental Protection Agency who has studied the effects of heat and air pollution on pregnancies. “It’s kind of like a double whammy for the same population.”
Here’s what we know about how pregnant women can navigate their health risks this pandemic summer:
Many studies have shown extreme heat poses especially serious risks to pregnant women.
There’s no question that extreme heat can be dangerous — even deadly — to human health. A July 1993 heat wave in Philadelphia resulted in 118 deaths, and two years later a July heat wave in Chicago resulted in 514 deaths, according to the CDC. And in Arizona, health officials identified more than 1,200 heat-caused deaths that occurred between 2008 and 2018.
If a young and healthy person overexerts themself in extreme or prolonged heat and doesn’t stay hydrated, it can lead to heat exhaustion, with symptoms including fatigue, muscle cramping, dizziness, and fainting. If left untreated, a person can develop heat stroke, which is life-threatening and causes fevers, confusion, and unconsciousness, as well as red, hot, and dry skin but no sweating. People who aren’t able to effectively regulate their internal temperatures, or “thermoregulate,” are far more at risk of experiencing a heat-related illness.
So who’s considered especially vulnerable? The most common groups include the elderly, people with preexisting conditions like heart or kidney problems, and young children, especially babies under the age of 6 months because they haven’t fully developed the ability to thermoregulate.
But pregnant women also fall into this category. The body has a lot of “tricks” to cool down, explained Nick Watts, a physician and climate expert, and “one of its main tricks is to pump blood faster; it moves blood through your veins faster and it increases cardiovascular output.”
But that’s more difficult for pregnant women, whose cardiovascular systems are already in overdrive. A pregnant woman who is trying to naturally cool down in extreme heat “is similar to flogging a workhorse,” Watts said. This is also why it can be so risky for a pregnant person to get a fever, whether from the flu, the coronavirus, or anything else.
Moreover, a small but growing body of research suggests a pregnant woman’s exposure to heat can put her at risk of other serious, lingering health effects.
For one, there’s the risk of delivering a baby early. Babies born prematurely are more likely to have breathing problems early on, be readmitted to the hospital post delivery, and die than those who are born after 39 weeks. They’re also more likely to have long-term health problems.
A 2010 study looking at about 60,000 births in California in the spring and summer months between 1996 and 2006 found “high ambient temperature was significantly associated with preterm birth for all mothers,” with Black mothers facing the highest risks. The researchers, relying on birth certificates and temperature data, found that with every 10-degree increase in the average weekly outdoor temperature, there was an 8.6% increase in deliveries before 37 weeks. A follow-up study in 2018 came to similar conclusions.
In a 2019 study, researchers used data on 56 million births across the US between 1969 and 1988 to see whether they were higher on hot days compared to the same dates during a different, cooler year.
“What we ultimately find is on a hot day — above 90 degrees — births were about 5% higher,” said study author Jessamyn Schaller from the National Bureau of Economic Research. “That’s a really large effect.”
They also found that on the day following extreme heat exposure, some births were accelerated by up to two weeks. “We estimate that an average of 25,000 infants per year were born earlier as a result of heat exposure,” the study authors wrote. The authors projected that as climate change continues to drive up temperatures, early births will continue to rise.
Other studies have found correlations between heat exposure during pregnancy and increased risk of hospitalization, stillbirth for preterm babies, and low birth weight.
Some of the studies found a woman’s access to air conditioning dampened these health risks. Moreover, they repeatedly found women of color, especially Black women, were more at risk of negative health outcomes — from being hospitalized during pregnancy to preterm delivery to stillbirths.
“Extreme temperature is one of the drivers, certainly not the only one, in the disparity of maternal health by race that we’ve seen,” said Maya Rossin-Slater, an assistant professor at Stanford who has studied the impacts of heat on pregnant women.
The pandemic summer is making it even harder to protect pregnant women from heat.
The coronavirus pandemic, which has already claimed roughly 150,000 lives in the US, adds yet another health risk to pregnant women already facing this summer’s extreme heat.
If you’re able to work from home, or don’t need to work, and you have access to air conditioning, these dual health risks may not be a major concern. But if not, the health crises may be compounding.
Cooling centers, which are public places that blast air conditioning, are the “mainstay” of many cities’ emergency plans for extreme heat, according to Aaron Bernstein, interim director of the Center for Climate, Health, and the Global Environment at Harvard University. “Even if coronavirus weren’t around, the cooling centers have real challenges” in attracting people, he said.
This year, pregnant women may not be willing to take public transportation to get to a cooling center out of fear of catching the disease, or they may be worried about overcrowding, even if social distancing and mask wearing were enforced and extra wash stations were available.
When cooling centers aren’t available, pregnant women without air conditioning at home may seek refuge in other indoor public spaces, like malls and libraries, where their chances of exposure to the coronavirus could increase. And if a city is experiencing a particularly bad coronavirus outbreak, some of these places may not even be open.
Another concern is that even if someone does have access to air conditioning at home, they may avoid using it as a way to cut down on costs this summer as more families face the pandemic’s devastating economic fallout.
“With drastic unemployment and the loss of incomes, I worry that people are just looking for expenses to cut,” said Alan Barreca, an economist and maternal health researcher who led the 2019 study on hot days and early births. The “I can tough this out” mentality could be dangerous for pregnant women, he added. “It’s just kind of difficult to climate control to optimal levels without running an air conditioner.”
Health experts say we need to be doing more to protect pregnant women during the summer.
Despite the immediate and long-term impacts that heat exposure can have on pregnant women, they are rarely identified as an at-risk population in a city’s heat guidelines.
“Pregnant women as an at-risk group to climate change are largely ignored,” Skye Wheeler, an emergencies researcher for the Women’s Rights Division of Human Rights Watch, told BuzzFeed News. If you look at the heat emergency plans for several major US cities including Boston and New York, you’ll see a lot of different groups mentioned, she explained, but “pregnant people aren’t.”
A BuzzFeed News review of the public heat guidelines for 25 of the largest US cities found only Chicago and Philadelphia listed pregnant people as especially vulnerable. The CDC also doesn’t recognize them as especially at risk to heat.
“There’s very little happening right now to think about this issue and raise awareness,” Wheeler said. She’s working on setting national guidelines on the health risks of extreme heat for outdoor workers, which can include pregnant women. “We know that pregnant people are often desperate to work and earn money, especially if they know they are not going to get paid maternity leave, which is common in this country. We don’t want to put them in a position where pregnant people aren’t hired. We want a heat standard that is good enough for all people, where everyone can work safely.”
Concerned about this issue, Adelle Monteblanco, a sociology professor at Middle Tennessee State University, helped put on a small training in El Paso, Texas, in 2018 about heat risks for local maternal healthcare providers.
In conversations with midwives, lactation consultants, and doulas (people who provide support to women during the birth process), Monteblanco learned there was a big knowledge gap on the issue. “They were all familiar with some heat illness symptoms and that they could communicate protective measures if there was a heat event that was hurting their community, but unfortunately many were unfamiliar with pregnant people and fetuses as being uniquely vulnerable,” Monteblanco said.
The resulting two-hour workshop sought to address this, providing specific tips and resources for a dozen or so participating healthcare providers.
“These extreme exposures are coming up more and more,” said Rachel Curtis, an El Paso doula who attended the training and has since folded information about heat risks into her conversations with pregnant women. “None of us had any idea this could cause preterm birth [or] fetal demise. Holy cow.”
But such conversations have yet to become commonplace among maternal healthcare providers.
“We need the medical community involved,” said Basu of the California Environmental Protection Agency.
But communicating these risks can be tricky. For one, what’s considered hot in one place is not in another. “I think across the country, people want a magic number, and I wish there was one,” said Monteblanco.
And then you take into account how many anxieties pregnant women, especially first-time moms, already have to contend with. “I never want to make women feel bad about the ways that their decisions are constrained because that’s not on them — that’s on their social, political, historical, structural constraints,” said Monteblanco.
“Instead of putting it on women, I really think everything else has to change.” ●