​Heat-related illness affects everyone in hot temperatures, pregnant people included. However, pregnant women should take extra precautions because they have to work harder to cool down – not only themselves, but that extra little person in utero, too.

"Many women have a lower blood pressure, particularly in the early part of pregnancy," says Dr. Janet Lyons, medical lead for high risk obstetrics, and an obstetrician-gynecologist for BC Women's. "Warm conditions bring blood to the skin to get rid of excess heat, potentially making a women's blood pressure even lower. This can result in people having headaches, feeling light-headed or even fainting."

Any of the symptoms of heat related illness can be worsened if a mom has underlying illnesses like obesity, kidney disease or heart issues.

"Many women experience Braxton Hicks contractions in pregnancy," says Lyons. "Keep in mind, dehydration can make these worse."

Although there is not strong evidence that hot weather can cause preterm labour, anyone who experiences more Braxton Hicks-type uterine activity than usual should be checked by their health-care provider.

"Like the rest of the public, drinking water, use of cooling fans and avoiding increased activity during extreme heat are all strongly recommended."