Environmental temperatures of over 25 degrees Celsius are associated with a significant increase in the risk of being misdiagnosed with gestational diabetes during pregnancy, warn Greek researchers.
They highlighted that misdiagnosis of the condition could lead to unnecessary insulin treatment and avoidable distress for prospective mothers.
“Our findings suggest the need to take into consideration environmental temperature”
Gestational diabetes affects around one in 20 pregnant women, occurring when the pancreas cannot produce enough insulin to compensate for a rise in blood sugars caused by pregnancy hormones.
It usually develops during the last three months of pregnancy, can be dangerous for both the mother and the unborn baby if not appropriately managed.
For example, it can result in large babies that lead to labour difficulties, and negative health effects for the newborn, including low blood sugar levels, jaundice, and respiratory problems.
Current tests compare fasting blood sugar levels with non-fasting blood sugar levels and if either of these values is above a certain level, gestational diabetes may be diagnosed.
But the researchers said that, given its associated complications, including stillbirth, there was a need to diagnose and manage gestational diabetes “appropriately”.
They noted that previous studies had indicated there were more cases in the summer, suggesting that it may be seasonal, but also that misdiagnosis could be more likely during that time of year.
Until now, no studies have investigated the impact of temperature on gestational diabetes diagnosis, said the study authors.
To determine the impact of environmental temperature on diagnosis, researchers from Alexandra Hospital in Athens examined data on over 7,500 pregnant women.
They found that, during summer, average non-fasting blood sugar values were higher compared to winter, while fasting sugar levels were not – independent of a range of other factors. This led to a 70% higher rate of gestational diabetes diagnosis, they stated in the European Journal of Endocrinology.
“Better screening should ensure that pregnant women are properly diagnosed for gestational diabetes”
The researchers then showed, using a smaller group of patients, that non-fasting blood sugar levels were twice as likely to be considered high at temperatures of over 25 degrees. It follows similar findings
Lead author Dr Eleni Anastasiou said: “Our findings suggest the need to take into consideration environmental temperature during interpretation of test results used to diagnose gestational diabetes.
“We hypothesise that the seasonal changes observed may be due to an increase in blood flow that may diminish sugar extraction from blood to tissue,” said Dr Anastasiou.
Her group will now focus on identifying improved screening tools during and after pregnancy, and carry out randomised controlled trials to investigate new insulin regimens for these patients.
“Better screening should ensure that pregnant women are properly diagnosed for gestational diabetes, ensuring they receive treatment only when their blood sugar levels can pose a danger for themselves and the baby, and avoiding unnecessary treatment and distress during pregnancy,” she said.