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Type 1 Diabetes

CGM in Pregnancy: What the Biggest Study Found

· 3 min read · Reviewed by GlucIQ Clinical Review Workflow
#pregnancy#cgm#cluster:pregnancy

Pregnancy with type 1 diabetes is a high-stakes balancing act. Your glucose matters more than it ever has — because it directly shapes your baby’s development and your birth outcomes.

For a long time, the standard tool was fingersticks. Then a landmark trial — called CONCEPTT — asked whether CGM changes the picture. The answer: yes.

What CONCEPTT did

CONCEPTT was a big, international randomized trial. Pregnant women with type 1 were split into two groups: one used CGM, one stuck with fingerstick testing. Then researchers compared outcomes — for the mother and the baby (Feig et al., 2017).

What it found

The headline result: CGM improved glucose control in pregnancy — better time in target range, and crucially, it mattered for the baby too.

  • Mothers using CGM spent more time in their target range.
  • Babies born to CGM users had better outcomes — including fewer large-for-gestational-age babies (babies born bigger than they should be, which is a real risk with high glucose in pregnancy).
  • The effect was biggest in the group that used CGM consistently.

The message is simple: in pregnancy, where every hour in range counts, CGM gives you a tool that fingersticks can’t — a continuous picture instead of snapshots.

Why pregnancy is different

  • Targets are tighter. Pregnancy glucose targets are stricter than everyday ones — the range you’re aiming for is smaller.
  • The stakes are higher. High glucose in early pregnancy affects organ development; late pregnancy it drives baby size.
  • You can’t feel the subtle stuff. A CGM shows you trends before they become problems.

What this means for you

If you’re pregnant or planning pregnancy with type 1: CGM should be on the table from day one. Ask your care team about it if it’s not already part of your plan.

And if you’re already using CGM, keep wearing it — the CONCEPTT data says consistent use is where the benefit lives (Feig et al., 2017).

The honest caveats

  • CGM is a tool, not a fix — the tight targets still require effort.
  • The trial found benefit, but it didn’t erase all pregnancy risks. Type 1 pregnancy remains high-stakes.
  • Your team’s guidance on targets and dosing is the real driver — CGM just gives you (and them) better information.

The bottom line

The biggest trial of its kind found that CGM measurably improves glucose control and baby outcomes in type 1 pregnancy (Feig et al., 2017). If you’re pregnant or planning, that’s a conversation worth having today — not at the next routine visit.

References

  • Feig DS, et al. Continuous glucose monitoring in pregnant women with type 1 diabetes (CONCEPTT): a multicentre international randomised controlled trial. Lancet. 2017. DOI: 10.1016/S0140-6736(17)32400-5