This meta-analysis pooled 21 studies and 5,650 pregnant women, comparing continuous glucose monitoring with self-monitored blood glucose in pregnancies complicated by gestational diabetes, with low-to-moderate risk of bias.
Glycaemic measures favoured continuous monitoring across the board: mean glucose lower by 0.24 mmol/L (95% CI -0.41 to -0.06), coefficient of variation lower by 0.78%, mean amplitude of glycaemic excursions lower by 0.22 mmol/L, and time above 7.8 mmol/L reduced by 2.19 percentage points. Clinical outcomes followed, with 8-35% reductions in caesarean delivery, macrosomia, neonatal hypoglycaemia and hyperbilirubinaemia. Medication use rose by 21%.
That last figure is worth reading as a mechanism rather than a harm. Continuous monitoring finds excursions that intermittent testing misses, which prompts earlier escalation to metformin or insulin, which is plausibly how the neonatal outcomes improved. The glycaemic differences themselves are small in absolute terms — 0.24 mmol/L is not much — so the benefit likely comes from better-targeted treatment rather than from the numbers alone. The review mixes randomised and observational studies, so the outcome estimates should be treated as encouraging rather than definitive, and cost remains the limiting factor in most settings.
- Mean glucose 0.24 mmol/L lower; time above range down 2.19 points
- 8-35% reductions in caesarean, macrosomia, neonatal hypoglycaemia and jaundice
- Medication use 21% higher — likely the mechanism, not a harm
- Randomised and observational studies pooled together; treat outcomes cautiously
The statistics, in plain English
The glycaemic differences are statistically significant but clinically small: a mean glucose difference of 0.24 mmol/L would not change management on its own. That the clinical outcomes improved considerably more than the glucose numbers suggests the benefit is mediated by what clinicians did with the extra information. Pooling observational studies with randomised ones tends to inflate apparent benefit, because women offered continuous monitoring differ systematically from those who are not.
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