Rationale and impact

Rationale and impact

These sections briefly explain why the committee made the recommendations and how they might affect practice.

Continuous glucose monitoring

Recommendations 1.3.17 to 1.3.20

Why the committee made the recommendations

There was evidence comparing real-time continuous glucose monitoring (rtCGM) with intermittently scanned CGM (isCGM) and with intermittent capillary glucose monitoring, for pregnant women with type 1 diabetes.

When compared with intermittent capillary glucose monitoring, rtCGM resulted in:

  • more women achieving their blood glucose targets

  • fewer caesarean sections

  • fewer neonatal intensive care unit (NICU) admissions.

One retrospective study was identified that compared isCGM with rtCGM. This study showed no clear difference between the 2 monitoring systems in maternal and neonatal outcomes.

Health economic modelling found that isCGM clearly has the lowest overall cost of the 3 options. It is much less certain that isCGM provides the most benefit (a finding that is in line with the clinical evidence). The committee were concerned by the very low quality of the evidence for isCGM, the accuracy of isCGM (particularly in the hypoglycaemic range) and the number of finger-pricks that would still be needed to use isCGM safely.

The committee agreed that all the uncertainties in the evidence would be likely to lead to the benefits of isCGM being overestimated. Therefore, they could not be confident that isCGM represents a better use of NHS resources than rtCGM, which had been shown in high-quality evidence to have better outcomes than intermittent capillary glucose monitoring and a 94% chance of being cheaper in the probabilistic sensitivity analysis.

Based on these findings, the committee recommended that rtCGM should be offered to all women with type 1 diabetes to help women meet their pregnancy blood glucose targets and improve neonatal outcomes.

The committee also noted that some women may be unable to use rtCGM or may prefer using isCGM instead. In these situations they recommended offering isCGM.

The committee amended the 2015 recommendation on considering rtCGM for pregnant women who are on insulin therapy but do not have type 1 diabetes because they wanted to identify specific scenarios in which rtCGM could be considered.

The committee believed that education and support are important for pregnant women using continuous glucose monitoring (CGM), to ensure they get the full benefit. Therefore, they updated and expanded the 2015 recommendation on providing support.

How the recommendations might affect practice

Use of CGM varies across the country, but most centres offer isCGM and/or rtCGM to pregnant women with type 1 diabetes (in accordance with the NHS long-term plan). Because of this, the recommendations are unlikely to cause a major shift in practice.

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