CGM use during pregnancy improves maternal glycemic control, neonatal outcomes
medwireNews: The CONCEPTT trial results suggest that the use of continuous glucose monitoring (CGM) by pregnant women with type 1 diabetes improves glycemic control and neonatal outcomes relative to standard glucose monitoring.
In light of these findings, “CGM should be offered to all pregnant women with type 1 diabetes using intensive insulin therapy during the first trimester,” study co-lead Helen Murphy (University of East Anglia, Norwich, UK) told delegates at the EASD annual meeting in Lisbon, Portugal.
CONCEPTT (Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial), the results of which were published simultaneously in The Lancet, included two parallel studies, one involving 215 pregnant women and the other 110 women who were planning a pregnancy. Murphy and colleagues randomly assigned participants to receive standard capillary glucose monitoring plus CGM, or standard monitoring alone.
Among the pregnant women, mean glycated hemoglobin (HbA1c) levels in the 108 participants receiving CGM fell from 6.83% at baseline to 6.23% at 24 weeks’ gestation and to 6.35% at 34 weeks, while the 107 women in the control group experienced a decrease in HbA1c levels from 6.95% at baseline to 6.40% at week 24 and to 6.53% at week 34.
These results translate into a “0.19% larger decrease in HbA1c levels among mothers randomized to CGM compared with those in the control group,” explained Murphy.
Pregnant women receiving CGM also spent a significantly greater proportion of time in the target glucose range of 3.5–7.8 mmol/L at week 34 than those undergoing standard monitoring alone (68 vs 61%), and the number of severe hypoglycemic episodes was comparable between the two groups (18 vs 21).
However, “to our surprise, we found no consistent benefit of CGM in women planning pregnancy,” said Murphy.
She explained that women who were planning a pregnancy experienced a greater decrease in HbA1c levels with CGM versus standard monitoring that was of “similar magnitude” to that observed in the pregnancy group, but the difference did not reach statistical significance.
Study co-lead Denice Feig (University of Toronto, Ontario, Canada) presented the neonatal outcomes for the pregnancy group. Although mean birthweight was not significantly different in the CGM and control groups, at 3545.4 g versus 3582.5 g, women receiving CGM were approximately half as likely to have large for gestational age babies (>90th centile) as women in the control group. There were also significantly fewer neonatal intensive care admissions lasting more than 24 hours and incidences of neonatal hypoglycemia in the CGM group (odds ratios of 0.48 and 0.45, respectively).
We now have proof that real-time CGM results in better pregnancy outcomes
“One needed to treat only six women with CGM to prevent one episode of large for gestational age; one needed to treat only eight women to prevent one neonatal hypoglycemia event, and six women to prevent one [neonatal intensive care unit] admission over 24 hours,” explained Feig.
Among the pregnant women, adverse events were reported in 48% of CGM participants and 40% of those in the control group, and a corresponding 7% and 5% experienced serious adverse events. The most frequently occurring adverse events in both groups were skin reactions (48 vs 8%), and the most common serious adverse events were gastrointestinal.
Commenting on the study at EASD, Elisabeth Mathiesen (University of Copenhagen, Denmark) asked: “Do I implement CGM to all pregnant women with type 1 diabetes in Copenhagen tomorrow?”
She believes that many women will ask for it, and that “we now have evidence-based data to consider CGM in selected pregnant women with type 1 diabetes,” but noted that the cost of CGM could prompt a reduction in other aspects of care.
And Mathiesen concluded: “The CONCEPTT study will change the future for pregnant women with type 1 diabetes.”
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