Staying safe in hot weather – Gestational diabetes and heat

Summer has arrived, so what does that mean for you as far as staying safe in the hot weather, plus gestational diabetes and heat are concerned?

Here are a few points to note which may make your gestational diabetes summer a bit more pleasant and levels a bit lower and more stabilised.

You may find a big difference in your blood glucose levels in hot conditions, so it’s important to be prepared!

gestational diabetes and heat


Hydration is so important during pregnancy; with gestational diabetes, we need to stay hydrated and then add hot weather and humidity into the mix and guess what? Yes, you need to drink even more to stay well-hydrated.

When you’re dehydrated, you have higher concentrations of blood sugar because less blood flows through your kidneys. With less blood, your kidneys don’t work as efficiently to clear out excess glucose from your urine, meaning higher blood glucose levels.

You shouldn’t be waiting until you are thirsty to drink; you should be drinking to ensure you do not become thirsty!

As always, water is your best option, but sugar-free drinks are fine too. See our drinks page for more information on drinks.


There is a risk of more hypos in hot weather for those taking insulin or Glibenclamide. Heat can increase the absorption of some fast-acting insulin, meaning you may need to test your blood glucose more often and perhaps adjust your dose of insulin.

Please note: you should consult a medical professional before adjusting your insulin dose unless you have been given guidance on how to do so safely.

The body’s metabolism is higher in hot and humid weather as it is working much harder, so if you take insulin or Glibenclamide to help control your blood glucose levels, then be prepared in case you have a hypo.

Know the symptoms of hypos and have a hypo kit to hand. To learn about hypos and how to treat them, please look at our hypo page.


Those not on insulin or Glibenclamide who notice low levels (levels below 4.0mmol/L) only need to eat a GD-suitable snack or their next meal to raise levels sufficiently, rather than treating their levels with anything high in glucose.

This is because those that aren’t on insulin injections can not drop to dangerously low levels as the body will release glucose to counteract the low levels. This is known as a ‘false hypo‘.

how to treat a hypo


Not only can you be affected by the hot weather, but your equipment can also be affected…

Blood testing in hot weather

Insulin, test strips and your blood glucose test monitor can be affected by extreme temperatures and so it’s best to keep your testing kit and insulin away from direct sunlight and extremely hot conditions.

Keep your insulin in a cool bag, but take care that it does not freeze if using an ice pack. Ideally, you want to keep your diabetes kits (monitors & test strips) at normal room temp and test your blood glucose levels in a cool, shaded place.

You can purchase specially designed cases for storing insulin and keeping your kit cooler in hot weather.

insulin cool pack
Signs that insulin has been heat damaged
  • Cloudy insulin looks ‘grainy’ and may stick to the side of the glass
  • Clear insulin may become cloudy
  • Insulin exposed to bright sunlight may turn ‘brownish’ in colour

Do not use insulin that shows any of these signs of damage. Please discard it and open a new insulin pen. If you have any doubt about whether ou insulin has been damaged, please consult a medical professional before taking it.


Many mothers say they do not feel like eating much in warmer weather; however, long periods without eating can harm your blood glucose levels.

When leaving a long time between eating, blood glucose levels drop low and the liver dumps stored glucose back into the bloodstream to raise levels. With gestational diabetes and diabetes in pregnancy, this can cause blood glucose levels to rise too high, causing a spike beyond the targets we are aiming to achieve.

Eating little and often is the best thing to ensure stable blood glucose levels. Ideally, three meals and three snacks a day (although these meals and snacks do not need to be much).

eat little and often


Be sensible in the sun; you’re a mummy!… you know the rules: sun cream, wear a hat, drink loads, avoid the hottest part of the day and don’t overdo it!

Heat exhaustion

People with diabetes are at higher risk of heat exhaustion. Symptoms include:
• Sweating more than usual
• Dizziness
• Cramping muscles
• Clammy skin
• Headaches
• Fast heartbeat
• Nausea

Consult a medical professional if you experience any of these symptoms


Have fun in the sun! We hope you have a great summer!

Why not buy some ice lolly moulds so that you can make sugar-free ice lollies or a slushy cup to make sugar-free slushies? We have lots of helpful info on our ice cream and BBQ pages that may be helpful too.

Ice Cream Lollies
Citrus Refresher
Citrus Refresher | A refreshing citrus drink to enjoy on hot summer's days | Gestational Diabetes UK
Check out this recipe
Citrus Refresher
Fake Pimms
Fake Pimms | Non-alcoholic | Gestational Diabates UK
Check out this recipe
Fake Pimms
As always, if you have any concerns, please seek advice from a medical professional