Glycaemic targets and monitoring for women with hyperglycaemia in pregnancy (including gestational diabetes)

Ideally, all pregnant women with hyperglycaemia in pregnancy (including gestational diabetes) should receive education about their diabetes and self-management from a credentialled diabetes educator. They should be advised to record blood glucose concentration results and dietary intake.

Capillary (finger-prick) blood glucose concentrations should be checked four times daily, before breakfast and after each main meal, with the 1 and 2 hour postprandial (after a meal) checks timed from the start of the meal. If the basal insulin requirement before bedtime is relatively high (eg 40 units or more of insulin), checking may also be needed before lunch and the evening meal, and daytime basal insulin may need to be added.

The frequency of blood glucose concentration checking may be reduced later if dietary intake remains satisfactory and glycaemic targets are achieved and maintained. However, checking should continue on at least 3 or 4 days each week, and recording dietary intake should continue based on individual need. The frequency of checking should be increased again if concerns about diet or the glycaemic profile arise.

For women with hyperglycaemia in pregnancy (including gestational diabetes) using blood glucose concentration monitoring (eg capillary [finger-prick] checking), suggested target ranges during pregnancy are given in Suggested blood glucose concentration targets for women with hyperglycaemia in pregnancy (including gestational diabetes). For women with hyperglycaemia in pregnancy (including gestational diabetes) using continuous glucose monitoring (CGM) or flash glucose monitoring, interstitial glucose concentration targets are not well-defined; the suggested targets for women with pre-existing diabetes in pregnancy can be used as a guide (see Suggested interstitial glucose concentration targets during pregnancy for women with pre-existing type 1 diabetes).
Table 1. Suggested blood glucose concentration targets for women with hyperglycaemia in pregnancy (including gestational diabetes)

[NB1]

Timing of blood sample

Blood glucose concentration target

First trimester (up to 10 weeks' gestation)

fasting and preprandial

4 to 6 mmol/L

1 hour postprandial

6 to 8 mmol/L

2 hours postprandial

5.5 to 7.5 mmol/L

Second and third trimester (from 10 weeks' gestation)

fasting

4 to 5.3 mmol/L

preprandial (before lunch and before evening meal)

4.5 to 5.5 mmol/L

1 hour postprandial

6 to 7.8 mmol/L

2 hours postprandial

5.5 to 6.7 mmol/L

If target blood glucose concentrations are not achieved, assess the dietary records and provide appropriate dietary guidance if necessary. This may be sufficient to correct blood glucose concentrations.

If blood glucose concentrations are consistently elevated at any particular time of day, start treatment according to the pattern of blood glucose concentrations (see Antihyperglycaemic treatment for women with hyperglycaemia in pregnancy (including gestational diabetes)).

If there is concern about intrauterine growth restriction, seek expert advice. Adjustment of blood glucose concentration targets may be needed.