Tommy's PregnancyHub

Testing your glucose levels with type or 2 diabetes

Managing your glucose levels can be challenging during pregnancy. It’s important to check your glucose levels regularly.

You may find it harder to tell when your glucose level is getting low (hypoglycaemia) when you are pregnant. Symptoms such as feeling sick or vomiting can affect your glucose levels too.

The following is based on the advice given by the National Institute for Health and Care Excellence (NICE) and is for guidance only. It’s a good idea to speak to your healthcare team about what’s best for you and your situation. 

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 may have more HbA1c tests later in pregnancy, although they may be less informative. Your care team can explain more about this.

Your target glucose levels (capillary glucose – home glucose monitoring)

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

If you are taking metformin or glibenclamide tablets or you are on insulin you should be advised to aim for the following target glucose levels (unless this causes hypoglycaemia):

  • fasting: below 5.3 mmol/litre and
  • 1 hour after meals: below 7.8 mmol/litre.

If you are not able to check until 2 hours (rather than 1 hour) after a meal, the target glucose level at that time is below 6.4 mmol/litre.

When to check your glucose levels (capillary glucose monitoring)

You care team should talk with you about when you should check your glucose levels during the day. 

If you have type 1 or type 2 diabetes and are managing your diabetes with 2 or more insulin injections a day, you should check:

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

If you have type 2 and are managing your diabetes with diet and exercise alone, taking metformin or glibenclamide or taking one insulin injection a day, then you should check:

  • fasting (before breakfast)
  • 1 hour after each meal.

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.

Using diabetes tech

If you have type 1 diabetes and are pregnant, you should be offered real-time continuous glucose monitoring (CGM) free on the NHS.

A CGM enables you to 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 low. 

How can I learn more about CGM?

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

Watch video clips from women sharing their experiences of using CGM in pregnancy and lots of useful top tips on how best to use your CGM at each stage of pregnancy on the Association of British Clinical Diabetologists website.

If you are using CGM, you should get support from your diabetes and pregnancy care team who are experienced in how to use it.

Insulin pumps

If you are finding it hard to keep your glucose in range or if you have hypoglycaemia, you may be offered an insulin pump.

This a small device that sends a steady flow of insulin through a fine tube inserted under the skin. 

Hypoglycaemia

Pregnancy can make it harder for you to recognise hypoglycaemia, and more severe hypoglycaemia events are common in the first 8 to 16 weeks of pregnancy. Make sure you have fast acting forms of glucose with you, such as sugar containing drinks or dextrose tablets. 

Your insulin needs 

Throughout pregnancy, insulin doses are always changing. During the first 8 weeks, they usually increase. This is usually followed by a reduction between 8 and 16 weeks. Your insulin dose will start to rise from about 16 weeks and continue to rise until around 35 or 36 weeks, when it should stabilise. 

If you are having frequent hypoglycaemic episodes or your insulin dose are dropping substantially in the third trimester, contact your healthcare team to check that everything is ok. 

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

Hazel

You will occasionally have high levels. Try not to worry too much about the occasional high reading. If your glucose levels are not regularly high, 1 or 2 readings that are out of the recommended range should not be a problem. Talk to your healthcare team if you have any concerns. 

NICE (2015). Diabetes in pregnancy: management from preconception to the postnatal period. National Institute for health and care excellence https://www.nice.org.uk/guidance/ng3

Teri B, Luther E (2019) Dawn phenomenon, StatPearls Publishing LLC.

Review dates
Last reviewed: 20 July 2020
Next review: 20 July 2023