Hypoglycaemia and pregnancy

Hypoglycaemia happens when your glucose levels drop below your target levels. It’s important to know the symptoms of hypoglycaemia if you’re pregnant and have diabetes.

On this page

What is Hypoglycaemia?

What causes low glucose?

Preventing low glucose levels

Symptoms of low glucose levels 

How to treat low glucose yourself

Hypo unawareness

Problems with hypoglycaemia

More about glucagon

More support and advice

What is Hypoglycaemia?

Hypoglycaemia (also known as a hypo) is when your glucose levels drop below target levels. It’s more likely to happen if you treat your diabetes with insulin.  It’s important to know how you can prevent your glucose levels from dropping below target during pregnancy.  

Hypoglycaemia is usually defined as a glucose level below 4mmol/l. However, some healthcare teams may use 3.5mmol/l instead during pregnancy. Talk to your healthcare team to find out your own target levels. 

Your glucose level will go up and down during pregnancy. In early pregnancy, you may experience an increase in the number of hypos you get. Talk to your healthcare team if this is the case. You may need to make some changes to your diet, lifestyle and medication.

Try to be realistic about how well you can manage your glucose level, while doing your best to stay healthy. You can talk to your healthcare team if you need more support, or you might find it helpful to look for peer support from other pregnant people. Diabetes UK provides details of local peer support groups.

What causes low glucose?

In people with diabetes, the main causes of low glucose are:

• taking too much insulin or medicines called sulphonylureas (such as gliclazide or glimepiride)  
• having issues with injecting insulin, such as injecting in the same place too often
• skipping a meal or leaving too big a gap before the next one
• eating less carbohydrate-containing food than planned  
• exercise or activity, especially if it's intense or unplanned  
• binge drinking, or drinking alcohol on an empty stomach. There is no known safe level for drinking during pregnancy, so the safest approach is not to drink at all while you're pregnant.  

Find out more about drinking alcohol in pregnancy, and diet and exercise in pregnancy with type 1 or diabetes.

Sometimes there's no clear reason why low glucose happens.

“I had the worst hypo I've ever had when I was pregnant. I woke up and the bed was wringing wet and I just couldn't think straight. Fortunately, my partner is aware of what to do, so he just said, ‘Right, where are your dextrose tablets?’”

Zoe 

Preventing low glucose levels

If you have diabetes, these tips can help reduce your chances of having low glucose levels:

• Check your glucose level regularly.
• Always carry a sugary snack or drink with you, such as dextrose tablets, a carton of fruit juice or some sweets. If you have a glucagon injection kit, keep it with you. Make sure your partner or a family member knows how to use it.
• Do not skip or delay meals.
• Take care when you have a workout. Eating a carbohydrate-containing snack before exercise can help reduce the risk of a hypo. If you take insulin, you may be advised to take a lower dose before or after you exercise.

Find out more about diet and exercise with type 1 and 2 diabetes.  

Symptoms of low glucose levels

A low glucose level causes different symptoms for everybody and yours may change when you are pregnant. 

Early signs of low glucose levels include:

• feeling hungry or dizzy
• sweating, shaking or trembling
• having tingly lips
• feeling tired or weak
• heart palpitations
• blurred vision
• turning pale
• getting easily irritated, tearful or confused (changes in mood).

If not treated, and sugar levels drop further, you might experience seizures or pass out. 

Hypos can also happen overnight, which may wake you up or cause headaches, tiredness or damp sheets from sweat in the morning. If this happens, talk to your healthcare team about your medication.

If you wear a continuous glucose monitor (CGM), set an alarm to alert you if your glucose levels drop overnight.

How to treat low glucose yourself

If your glucose is less than your lower target:

1. Have a sugary drink or snack. Try something like a small glass of non-diet fizzy drink, a 200ml carton of apple or orange juice, a small handful of sweets or 4 or 5 dextrose tablets.
2. Test your glucose via your CGM or finger prick after 10 to 15 minutes. If it's 4mmol/l or above and you feel better, move on to step 3. If it's still below 4mmol/l, treat again with a sugary drink or snack and take another reading in 10 to 15 minutes.
3. Once your blood sugar is above 4mmol/l, eat your main meal (containing carbohydrate) if you're about to have it. Otherwise, have a carbohydrate-containing snack – this could be a slice of toast with spread, or some biscuits.

Hypo unawareness

Pregnancy can make it harder for you to recognise hypoglycaemia, especially in the first trimester. It’s vital that you and the people you spend time with (such as your partner, friends or work colleagues) can spot hypoglycaemia and know how to help if you need it.  

If you take insulin, always try to have a fast-acting form of glucose with you, such as dextrose tablets or glucose-containing drink.

If you have type 1 diabetes, your care team should also provide you with glucagon. This can be injected to increase your glucose in an emergency. Your partner or family members should be shown how to do this.

Problems with hypoglycaemia

If you have type 1 diabetes, or problems with hypoglycaemia, you may be offered real-time continuous glucose monitoring (CGM) with alarms. If you have CGM, you will be given more information online about managing hypos.

If you are having regular hypoglycaemic episodes, you may be offered an insulin pump instead of injections. This is a small device that delivers a steady flow of insulin through a fine tube under the skin.

Some healthcare teams may offer CGM and insulin pumps to all pregnant women with diabetes. Speak to your team about your options.

More about glucagon

Glucagon is a hormone that can raise glucose levels. It is used to treat severe hypoglycaemia. If you have been given a glucagon kit, your team can show your friends, family and colleagues when and how to use it.

You might need to use it (or have it given to you) if:

• you are unconscious
• you have a seizure
• your blood glucose levels are not rising even though you have tried to treat it yourself with sweet food or drink 3 times
• for some reason you cannot eat or drink something sweet – for example, if you do not have anything, or if you are being sick and cannot keep food down.

If you have a seizure or become unconscious, anyone who is with you should call an ambulance right away!

The kit will include 2 bottles – one of liquid and one of glucagon powder – which need to be mixed, and a syringe.

Injecting glucagon: a quick guide

1. Put the person on their side in the recovery position as glucagon may make them vomit.
2. Check the expiry date on the kit. If it’s out of date, don’t use it. Call for emergency help instead.
3. If it’s in date, follow the instructions on the kit to mix the glucagon.
4. Inject the glucagon into the person’s arm, buttocks or thigh.
5. The blood glucose levels may take several minutes to rise. If the person hasn’t recovered within ten minutes, call an ambulance.  

These instructions are just a general guide. Speak to your healthcare team for specific advice on how and when to use your glucagon kit, and share that information with friends and family.

More support and advice

If you’re struggling to manage your blood sugar levels, speak to your healthcare team. If you’re worried about any symptoms you’re having, you can always call NHS 111 for immediate health advice.
The charity Diabetes UK have more information on diabetes and pregnancy. If you have further questions or need support, you can call their helpline on 0345 123 2399 (9am to 6pm, Monday to Friday), or email [email protected] 
Learn how diet and exercise can help manage your blood glucose levels during pregnancy.