How to

8 September 2016

Exposure to Extreme Temperatures Increases Risk of Preterm Birth

We have long known that pregnant women have to take special care of their bodies, lest they inadvertently cause harm to their unborn child. Activities such as smoking, drinking and drug use have been proven to have highly negative effects on the development of a baby, but a new study suggests that even something as mundane as the weather can actually have some startling, and worrying, results.

The study, conducted by the National Institutes of Health (NIH) in the US, analysed the medical records of 223,375 women who gave birth between 2002 and 2008 at one of 12 medical centres spread throughout the country. They wanted to know if exposure to extreme temperatures had any noticeable effect on the child’s development; specifically if it had any influence on the likelihood of preterm birth (preterm birth is defined as birth before the 37th week of pregnancy). Extreme temperature in this case was given a very specific definition: extreme heat is defined as above the 90th percentile of average temperatures, extreme cold is defined as anything below the 10th percentile, and mild temperatures cover everything in between.

Compiling their own data with hourly temperature data from the Weather Research and Casting Model, the researchers were able to determine that temperature does indeed play a role in this process.

For example, they found that those subjected to extreme heat during their first 7 weeks of pregnancy were 11% more likely to give birth before 34 weeks, and 4% more likely to give birth before 37-38 weeks.

On the other hand, those who experience bouts of extreme cold during the first 7 weeks of pregnancy were found to be 20% more likely to give birth before 34 weeks, 9% more likely to deliver before 34-36 weeks, and 3% more likely to see their baby before 37-38 weeks.

The effects of exposure to extreme temperature diminish after the 7 week mark, but subjecting yourself to extremes between the 8th and 14th week will still increase your likelihood of a preterm birth by some degree.

With all this in mind, expectant mothers are being advised to avoid such conditions as much as possible, particularly during summer months. The effects of extreme cold are easier to counteract with a few extra layers; when temperatures rise, getting yourself to a comfortable temperature is a much more difficult task, so take care out there all you mums-to-be.

Sam Bonson

Sam is an aspiring novelist with a passion for fantasy and crime thrillers. He is currently working as a content writer, journalist & editor in an attempt to expand his horizons.