Testing your glucose levels with type 1 or 2 diabetes

Managing your blood sugar levels can be a challenge in pregnancy. It’s important to check your glucose levels often. You may be offered continuous glucose monitoring (CGM) for checking your levels.

On this page

Your glucose levels in pregnancy

HbA1c levels

Your target blood glucose levels in pregnancy

When to check your glucose levels (capillary glucose monitoring)

Managing your glucose levels if you are on insulin

Insulin pumps

Hypoglycaemia

Your insulin needs

More support and advice

Your glucose levels in pregnancy

You may find it harder to tell when your glucose level is getting low (hypoglycaemia) when you are pregnant. Feeling sick or being sick can affect your glucose levels too.

Both diabetes and pregnancy affect everyone differently. Your healthcare team will work with you to find the best way to look after you and your baby during pregnancy. This information is for guidance only – always speak to your healthcare team if you have any questions or concerns.   

HbA1c levels

This tells you your average glucose levels over the last 2 to 3 months. You should be offered an HbA1c test at your booking appointment.

You should be offered another HbA1c test again at the start of the third trimester. You may also be offered more HbA1c tests at other times during your pregnancy.

HbA1c tests in the second and third trimesters may not be as reliable as earlier tests. This is because changes to your blood during pregnancy can make it harder to accurately measure HbA1c levels. Your care team should explain more about this.

Your target blood glucose levels in pregnancy

You and your care team should agree target glucose levels that are right for you and can be managed without causing problems with hypoglycaemia.

You should usually be advised to aim for the following capillary glucose levels, unless this causes problems with hypoglycaemia:

• fasting: below 5.3 mmol/litre
• 1 hour after meals: below 7.8 mmol/litre  
• 2 hours after meals: below 6.4 mmol/litre.

If you’re taking insulin, you should usually be advised to keep your capillary glucose level above 4mmol/litre.

This information is for guidance only, always check with your healthcare team about your own personal targets.  

When to check your glucose levels (capillary glucose monitoring)

Your care team should talk with you about when you should check your blood sugar levels during the day.  

Continuous glucose monitoring

If you have type 1 diabetes and are pregnant, you should be offered real-time continuous glucose monitoring (CGM) for free on the NHS. Your healthcare team may also offer this if you have type 2 diabetes and your blood glucose levels are difficult to control.

A CGM lets you check your sugar levels at any time, shows you patterns in your levels, and sends you an alert if your sugar levels are too high or too low.

If you are using CGM, you should get support from your diabetes and pregnancy care team, who are experienced in how to use it. You may also be asked to do finger-prick testing.  

The NHS has more information online about CGM and using CGM throughout all stages of your pregnancy.

Using testing strips

If you have type 1 diabetes, or you manage type 2 diabetes with 2 or more insulin injections a day, you should usually check:

• when you wake up (before breakfast)
• before other meals
• 1 hour after each meal
• at bedtime.

If you have type 2 diabetes and manage it with either diet and exercise, metformin or 1 insulin injection a day, then you should usually check:

• when you wake up (before breakfast)
• 1 hour after each meal.

Talk to your healthcare team for more information on exactly when and how to test your glucose levels during pregnancy.

You may be more resistant to insulin around breakfast time. This is known as the dawn phenomenon. Talk to your healthcare team if your fasting glucose levels are always high.

Managing your glucose levels if you are on insulin

If you have type 1 diabetes, your care team should 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.

Insulin pumps

You may be offered an insulin pump to help manage your glucose levels during pregnancy. This a small device that sends a steady flow of insulin through a fine tube under the skin.  

Insulin pumps are usually recommended if you are finding it hard to keep your glucose in range, or if you have hypoglycaemia. Speak to your healthcare team for more information.

Hypoglycaemia

Pregnancy can make it harder for you to see the signs of hypoglycaemia, especially in the first 3 months. Make sure you have fast acting forms of glucose with you, such as drinks that contain sugar, or dextrose tablets.  

Learn more about hypoglycaemia in pregnancy.

Your insulin needs

Throughout pregnancy, insulin doses are always changing. You may need less insulin between around 9 and 16 weeks. Your insulin dose will start to rise again until around 35 or 36 weeks, when it should stablise.

Your healthcare team will work with you to find out the exact amount of insulin you need, so follow their guidance.

If you are having frequent hypoglycaemic episodes, or your insulin doses are dropping a lot in the third trimester, contact your healthcare team to check all is well.  

After you have your baby, insulin requirements drop. Your healthcare team will provide you with a postnatal plan for insulin doses.

“Because I had to get my control very fine, it was almost like learning to live with diabetes all over again. I had to change quite a lot from when I was first diagnosed.” 
Hazel

Glucose levels may sometimes be high. If yours are above your target levels, your healthcare team should tell you what to do next.  

If you have been given ketone testing strips, you may be advised to use them if your blood glucose levels are above 10mmol/l2. If your ketones are high – or you become hyperglycaemic and don’t have ketone testing strips - seek urgent medical advice, especially if you feel unwell.

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.