- A multinational trial of 375 women with gestational diabetes found that real time continuous glucose monitoring reduced the risk of having a large for gestational age baby compared with standard finger prick testing.
- In the continuous monitoring group, 4 percent of women had a large baby compared with 10 percent in the usual self monitoring group and average birth weight centiles were lower.
- More babies than expected in both groups had low birth weight, which suggests that very tight glucose control might restrict growth and that pregnancy glucose targets may need further refinement.
Researchers in Austria, Germany and Switzerland ran the GRACE trial, an open label, randomised controlled study at four university centres, including the Medical University of Vienna and Charité in Berlin.
They recruited 375 women with gestational diabetes and randomly allocated them to either real time continuous glucose monitoring or standard self monitoring of blood glucose using finger pricks.
All women received guideline based care for gestational diabetes from diagnosis until delivery. The only difference between groups was how glucose levels were measured and displayed.
Key results
When birth data were analysed, there was a clear benefit for women who used continuous glucose monitoring.
Only 4% of women in the real time continuous monitoring group had a baby classified as large for gestational age.
In the finger prick group, 10 percent of women had a large for gestational age baby.
Average birth weight centiles were also lower in the continuous monitoring group, which suggests that babies in this group were less likely to grow excessively.
There were no important differences in serious adverse events between the two groups. However, the researchers noticed that in both groups there were more babies than expected who were small for gestational age.
- How do I prevent gestational diabetes?
- Exercising with gestational diabetes
- Postpartum screening low among women affected by gestational diabetes or hypertension
One possible explanation is that very strict glucose management could limit growth in some pregnancies.
The authors state that this finding needs further investigation and that optimal glucose targets in gestational diabetes still need to be defined more precisely.
The study was funded by Dexcom, a manufacturer of continuous glucose monitoring systems, and published in The Lancet Diabetes and Endocrinology.
What this means for pregnancy care
Continuous glucose monitoring uses a small sensor placed under the skin to provide glucose readings throughout the day and night.
It allows pregnant women with gestational diabetes to see how meals, activity and insulin affect their levels in real time and to make timely adjustments in partnership with their clinical team.
The GRACE trial suggests that real time continuous monitoring can reduce the risk of having a larger baby in women with gestational diabetes without increasing serious complications, although the higher than expected rate of smaller babies shows that care is needed not to push glucose too low.
In the United Kingdom, continuous glucose monitoring may not be routinely offered to every woman with gestational diabetes.
It is more likely to be considered if you need insulin, find it hard to keep glucose in range or would benefit from closer monitoring.
Decisions about using continuous monitoring should be made with your diabetes in pregnancy team, who can weigh up the potential benefits, costs and practicalities for your individual situation.
Whatever monitoring method is used, early diagnosis and consistent treatment of gestational diabetes remain essential to lower the risk of complications for both mother and baby.
