CGM for Gestational Diabetes: What a New Trial Found

What Was Studied and Why It Matters

Gestational diabetes mellitus (GDM) — a form of diabetes that develops during pregnancy — is becoming more common and can raise the risk of complications for both mother and baby. Managing blood sugar carefully throughout pregnancy is one of the most important ways to protect both.

Researchers wanted to know whether using a real-time continuous glucose monitor (RT-CGM) — a small sensor worn on the body that tracks blood sugar around the clock — would help pregnant women with GDM keep their glucose levels in a healthier range compared to traditional finger-stick blood sugar checks.

How the Study Worked

105 pregnant women diagnosed with gestational diabetes were randomly placed into one of two groups:

• RT-CGM group (53 women): Could see their glucose readings in real time on a device or smartphone app
• Blinded CGM group (52 women): Wore a sensor that recorded data, but they could not see the readings — they still checked blood sugar the traditional way with finger sticks

Researchers tracked how much time each woman spent with blood sugar in the healthy target range (63–140 mg/dL), along with average glucose levels, medication use, and pregnancy outcomes.

What the Researchers Found

The results were more complicated than expected:

• Time in healthy glucose range was nearly identical between both groups (about 93%) — no significant difference
• Average blood sugar was slightly higher in the RT-CGM group (106.7 mg/dL vs. 98.1 mg/dL), though both averages are within a reasonable range
• More women in the RT-CGM group needed insulin or metformin (67% vs. 33%) — possibly because seeing real-time data made both patients and doctors more aware of blood sugar spikes
• No differences in birth or pregnancy complications were found between the two groups
• 31 out of 52 women in the blinded group dropped out — and 30 of them said they left specifically because they wanted access to real-time readings

What This Means for Real Patients

This study suggests that CGM alone — when started around 30 weeks of pregnancy — may not dramatically change blood sugar control compared to finger-stick testing. However, the overwhelming desire among participants to use real-time monitors is a powerful signal that pregnant women with GDM want this technology.

The high dropout rate in the blinded group also makes the results harder to interpret. It's possible that starting CGM earlier in pregnancy, or focusing on higher-risk patients, could show clearer benefits in future research.

If you're managing gestational diabetes and considering a CGM device, talking with your care team is the first step. For those already using CGM or needing reliable diabetes supplies during pregnancy, MDS Diabetes offers a range of monitoring tools and support to help you stay on track.

Bottom Line

A real-time CGM didn't significantly outperform finger-stick testing in controlling blood sugar for gestational diabetes in this trial — but patient demand for the technology was striking, and more research is needed. If you have GDM, speak with your doctor about whether CGM is right for your situation.