Safety for the perinatal population during extreme heat

Safety for the perinatal population during extreme heat

Last Updated: July 27, 2022
HealthLinkBC File Number: 35a
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Heat and humidity can go up in the summer months, making it feel hotter outside than normal. Extreme heat happens when the heat and humidity are much higher than we would expect during a normal summer day.

Extreme heat can be harmful to anyone's health, but people who are pregnant or had a baby within the past 6 weeks may be at a higher risk. Weight normally gained during a pregnancy can make it harder for the body to maintain a safe body temperature during hot weather – this can lead to heat-related illness.

Extreme heat may raise the risk of preterm birth, low birth weight, and stillbirth.

By protecting yourself from extreme heat, you can help reduce these risks.

If you experience heat-related symptoms or increased contractions it is important to speak with your registered midwife, family physician, or obstetrician. You can also call HealthLink BC at 8-1-1 anytime to talk with a registered nurse.

What can you do to keep safe?

Keep a cool space

  • Turn on air conditioning (AC) if you have it. A temperature of <26°C is safe for most people
  • Go to local cooling centres or community spaces, such as libraries or malls
  • Sleep in the coolest room in your home, even if it is not your bedroom
  • Close windows during the heat of the day to trap cooler air inside
  • Cover windows by using shutters, blinds, drapes, blankets or sheets to keep sun out during the day
  • If the temperature drops at night and it is safe, open windows to let cool air in
  • If you have a fan, use it to move air around the room. Keep in mind that fans might not help to lower your core body temperature when it is very hot
  • Turn off lights and electronic devices that are not in use to avoid any extra heat
  • Use your oven or stove as little as possible as this can spread heat throughout your home

Keep your body cool and hydrated

  • Drink plenty of water and other fluids (about 3-4 litres of water a day), especially if you are breast/chest-feeding
  • Avoid drinking large amounts of caffeinated, sugary or artificially sweetened and alcoholic drinks
  • Eat fruits and vegetables. They have a high water content and can help keep you hydrated
  • Take a cool shower or bath or try a sponge or foot bath
  • Try using a cold pack or wrap
  • Wear light-coloured, loose-fitting, breathable clothing, sunglasses and a wide-brimmed hat if you are outside. Although light-coloured clothing is recommended to keep cool, it does not provide as much SPF protection from the sun's rays as darker coloured clothing
  • Protect exposed skin by wearing sunscreen with broad-spectrum coverage and a Sun Protection Factor (SPF) of at least 30

If you are breast/chest-feeding, try to limit your caffeine intake to 300 mg per day (about 11/2 cups of coffee) and no alcohol intake.

If you are tandem feeding during pregnancy, it's important for you to stay hydrated. Try having a cool non-alcoholic, low-sugar drink during every feed in addition to other drinks throughout the day.

Keep out of the heat

  • If you have to go outside, try to stay in cooler areas like large, shaded parks or spaces near big bodies of water
  • Try to plan activities, such as going to appointments, during the cooler morning and evening hours. This might make it easier to stay inside in a cool place during the hottest hours of the day
  • If you work outside or in an environment that does not have a good cooling system, such as air-conditioning, talk to a health care provider or workplace safety officer to find out what measures exist to reduce your risk of heat-related illness

What are symptoms of mild to moderate heat-related illness?

Some symptoms of mild to moderate heat-related illness include:

  • Irritability
  • Thirst
  • Fast heart rate even when resting
  • Feeling generally unwell
  • Heavy sweating
  • Muscle cramps
  • Rash
  • Swelling, especially in hands and feet
  • Fatigue and weakness
  • Dizziness
  • Headache
  • Peeing less, and urine is very dark
  • Body temperature of >38°C (100°F)

Most mild/moderate heat-related illnesses, sometimes called heat exhaustion, can be treated at home if they are caught early. If you are showing signs of mild/moderate heat-related illness, start cooling yourself down right away. If your symptoms last longer than 1 hour, change, worsen or cause you concern, contact a health care provider.

What are symptoms of severe heat-related illness?

Some symptoms of severe heat-related illness include:

  • Hot and flushed or very pale skin
  • Not sweating
  • Severe nausea and/or vomiting
  • Fainting or loss of consciousness
  • Increased heart rate and rapid, shallow breathing
  • Unusual confusion and decreased mental alertness
  • Difficulty speaking
  • Unusual coordination problems
  • Peeing very little, and urine is very dark
  • Body temperature of >39°C (102°F)

Call 9-1-1 if you suspect a severe heat-related illness and keep trying to cool the individual until help arrives.

Contact your healthcare provider or go to the hospital right away if you have these signs of preterm labour:

  • A trickle or gush of fluid or bleeding from your vagina that doesn't stop after going to the bathroom
  • Stomach pains or bad cramps that won't go away
  • Unusual lower back pain or pressure
  • Contractions that don't go away when you walk, rest, or take a warm shower
  • A feeling that something isn't right

BC's new heat alert warning system

The B.C. Heat Alert and Response System, or BC HARS, defines two categories of heat events – heat warning and the more dangerous extreme heat emergency – triggered by specific temperature ranges to initiate recommended response actions. Environment and Climate Change Canada issue the alerts and you can sign up to get heat push notifications to your smartphones through the WeatherCAN app for any/all of the pre-selected locations.

For more information

For more information on extreme heat, see:

For more information on heat-related illness and keeping children safe during extreme heat, see:

For more information on foods and drinks to limit or avoid during pregnancy or breast/chest-feeding, please visit: