Climate change could affect pregnancies and newborns' health, study shows

A new study that rising temperatures brought on by climate change could be shortening pregnancies by as many as two weeks suggests worrisome implications for babies' health and children's later development.

The study by University of California, Los Angeles, found that births on hot days 90 degrees and higher were happening much earlier than expected – as many as 14 days sooner. Pregnancies generally last 40 weeks.

“That's enough to take somebody from what's considered to be a pretty healthy pregnancy into a ‘we are somewhat worried' pregnancy,” the study's lead author, UCLA professor and environmental economist Alan Barreca, said in a story on the findings this month for the UC system.

The research by Barreca and co-author Jessamyn Schaller – a professor at Claremont McKenna College whose research focuses on economic conditions' effects on child welfare – showed birth rates rose by 5 percent on days when the mercury rose above 90 degrees.

The study examined the effect of hot weather on early deliveries. The team's research appeared Dec. 2 in the journal Nature Climate Change.

“It was the first thing that jumped out at us: How much of an acceleration (in gestation times) did we see,” Barreca told The Sacramento Bee in a recent interview. “We identified days where there were drops in birth rates. (Pregnancies) shortened by up to two weeks, but the average was six days.”

Barreca and Schaller, both UC Davis graduates, culled exhaustive birth data – 56 million records between 1969-88 – for their study, matching recorded birthplaces to daily weather data.

The data is a “significant time period,” Barreca said.

“A lot of homes were adopting air conditioning during this time period,” he said, adding that their research showed the climate control systems had a positive impact on pregnancy lengths during that 20-year span.

About 25,000 births were affected each of those years, the researchers found. Birth rates soared when days topped 90 and fell again during cooler weather.

As temperatures climb with climate change, the study estimates another 42,000 births a year will be affected by 2100.

“One thing that's an important takeaway, (heat) has affected a lot of births in the U.S. – 25,000 per year in our study. We predict with climate change an additional 42,000 births (by 2100),” Barreca said. “That's a very big number – one in 100 births. This is a very high risk. The birth implications of climate change affect people the most.”

Hot weather is potentially a risk factor in early child births, Barreca explained for the environmental news website EcoWatch this month. Heat exposure can increase levels of oxytocin, a hormone that regulates delivery, he said.

Heat isn't the only indicator of early deliveries. Socio-economic factors, including ready access to prenatal and other health care, also play significant roles.

Florida, Georgia and Mississippi – states in the warmer weather Deep South – each have uninsured rates of 10 percent or higher, all above the 8.9 percent U.S. average, according to Census data.

“Questions remain about the number of deliveries affected by hot weather every year in the U.S.,” or if it factors into the timing of childbirths, Barreca said in EcoWatch.

But Barreca told The Bee that long-term outcomes of children exposed to environmental effects have potential consequences: “If they're exposed to pollution or intense heat, they're not doing well in school and could factor into their entry into the labor market.”

He has been studying the impacts of weather on health for the past decade.

“At the start of my career, I was in awe of how different child health is in the U.S. – how families in hotter climates tend to be unhealthier,” he said. “Could it be an accident of history? Institutional or historical racism? And if it it's hotter weather, can we do something about it?”

One solution, he said, is broader access to affordable air conditioning – and as important, more environmentally friendly climate systems and renewable energy sources

The study makes the point that climate change and its effect on families is as much about economic justice as it is environmental justice.

“We want to make the point that air conditioning is expensive and that's putting a lot of families making tough decisions,” Barreca said. “It's a really difficult issue for low-income families.

Barreca says California can prove an example of how to balance the scale for families without ready or affordable access to air conditioning. He points to the state's California Alternate Rates for Energy program.

CARE provides low-income customers enrolled in the program with 30 to 35 percent discounts on their electric bills and 20 percent discounts on natural gas bills.

“It's an example of how we can help families through policy,” he said.