Your blood glucose levels during pregnancy

Testing your blood glucose levels

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

Diabetes type and treatment

When should I test?

Women with type 1 diabetes

  • Fasting (before breakfast)

  • Before other meals

  • 1 hour after all meals

  • Bedtime

Women with type 2 diabetes or gestational diabetes having 2 or more insulin injections a day

  • Fasting (before breakfast)

  • Before other meals

  • 1 hour after all meals

  • Bedtime

Women with type 2 diabetes or gestational diabetes having any of the following:

  • Fasting (before breakfast)

  • 1 hour after all meals

Blood glucose target levels

You and your care team should agree ideal (or target) blood 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 blood glucose levels, unless this leads to difficulties with hypoglycaemia:

  • fasting: below 5.3 mmol/litre

    and

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

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

If you are on insulin or glibenclamide, you should also be advised to keep your blood glucose above 4 mmol/litre, because of the risk of hypoglycaemia.

HbA1c levels

An HbA1c test tells you your average blood glucose levels over the last 2 to 3 months.

  • If you already have diabetes, you should be offered an HbA1c test at your booking appointment. HbA1c tests might also be carried out later in pregnancy, although they are a less precise estimate of your blood glucose levels as pregnancy goes on. Your care team can explain more about this.

  • If you are diagnosed with gestational diabetes, you should be offered an HbA1c test as soon as possible once diabetes is confirmed, to make sure that you don't have type 2 diabetes.

Managing your blood glucose levels if you are on insulin

Your care team will review your insulin treatment with you, and may suggest a different type to help you achieve your blood glucose targets.

Your care team should explain how being pregnant can make it harder for you to recognise hypoglycaemia, especially in the first 3 months. You should make sure you have fast‑acting forms of glucose, such as sugar‑containing drinks or dextrose tablets, to hand in case your blood glucose gets too low.

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

If you are finding it hard to keep your blood glucose at the right level or hypoglycaemia is affecting your day‑to‑day activities, you may be offered an insulin pump (a small device that delivers a steady flow of insulin through a fine tube inserted under the skin) instead of injections.

Occasionally, pregnant women are offered a machine for 24‑hour monitoring of glucose levels – called continuous glucose monitoring, or CGM – but only if they have serious problems with hypoglycaemia or controlling their blood glucose.If you have CGM, you should be given a phone number so that you can contact a member of your care team who is expert in its use for advice and support if needed .

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