Summer Pregnancies May Have Higher Risk for Gestational Diabetes


A summer pregnancy could increase the risk for gestational diabetes, according to a new study.

Gestational diabetes, a form of high blood sugar that affects pregnant women, puts women who develop the condition at risk for Type 2 diabetes as well as other health issues. It can raise the risk of premature birth as well as the child’s likelihood of developing Type 2 diabetes.

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“Based on the study’s findings we would expect pregnancies in warmer climates to be at higher risk of gestational diabetes, although we weren’t able to look at that directly,” said Gillian Booth, a researcher at St. Michael’s Hospital and the Institute for Clinical Evaluative Sciences in Toronto, to CNN Health. “I think that’s a great topic for future research.”

The study aimed to look at the relation between outdoor air temperature and the risk of developing gestational diabetes. Using administrative health databases, the researchers identified every birth in the Toronto, Canada, area from 2002 to 2014.

“In our setting, there was a direct relation between outdoor air temperature and the likelihood of gestational diabetes mellitus,” the study authors wrote. “Future climate patterns may substantially affect global variations in the prevalence of diabetes, which also has important implications for the prevention and treatment of gestational diabetes mellitus.”

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During the 12 year period, there was a recorded 555,911 births among 396,828 women. There was a 4.6 percent prevalence of gestational diabetes for women who were exposed to extremely cold outdoor weather temperatures 30 days before giving birth.

The prevalence of gestational diabetes was increased to 7.7 percent when women were exposed to hot temperatures. Every ten degree increase in an average 30 day temperature was associated with a 1.06 times higher odds of developing gestational diabetes.

The study adjusted for maternal age, equality of pay, neighborhood income, world region and year. Booth said that though the study didn’t specifically focus on seasons, the was a significant spike in the days with higher temperatures.

“Although we didn’t look at seasons per se, rates were highest when that 30-day window happened in the summer when the temperature was hottest,” she said. “[The study] offer[s] fairly compelling evidence that air temperature may be a modifiable risk factor for gestational diabetes.”

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Booth said she recommends achieving a healthy body weight before conception, avoiding excess weight gain during pregnancy, eating a healthy diet and staying physically active as ways to reduce the risk of gestational diabetes.

Strategies such as using air conditioning and ditching excess layers of clothing during the summer could also influence risk for gestational diabetes. While temperature may have a small effect on the risk of developing the condition, it could be a tipping point, she said.

“It is one factor that might be sufficient to push someone’s risk over the edge,” Booth said.

The study was published in the Canadian Medical Association Journal.