Type 1 diabetes during pregnancy linked to increased risk of hypoglycemic episodes

USA: Pregnant women with type 1 diabetes have a sustained daytime risk of hypoglycemia, which tends to happen more frequently overnight during pregnancy, states a study published in the journal of Diabetes Technology & Therapeutics.

Up to 10% of all pregnancies in the US are complicated by diabetes. 0.2% to 0.5% of these are people with type 1 diabetes (T1DM). With traditional insulin replacement therapy, hypoglycemia, especially at night, is a frequent occurrence. Type 1 diabetes carries a high risk for pregnancies, and there is little information available in the United States about hypoglycemia based on continuous glucose monitoring (CGM) during pregnancy in patients using sensor-assisted insulin pump therapy.

The authors of the study aimed to record hypoglycemia during pregnancy in women on sensor-assisted insulin pump therapy and using continuous glucose monitoring (CGM).

For this purpose, 25 pregnant women's data were examined for CGM hypoglycemia using international consensus recommendations for percentage time <63 and 54 mg/dL, hypoglycemic events, persistent hypoglycemia events for 24-h, daytime, and nocturnal periods, and severe hypoglycemia (SH) episodes. Before 17 weeks of pregnancy, type 1 diabetic pregnant women were enrolled in the LOIS-P Study (Longitudinal Observation of Insulin use and glucose Sensor metrics in Pregnant women with type 1 diabetes using continuous glucose monitors and insulin pumps). The authors used a study Dexcom G6 CGM in addition to their own insulin pump.

Key findings of the study:

• The biweekly median percentage of time 63 mg/dL over a 24-hour period varied greatly throughout pregnancy, from 0.8% at biweek 4-5 to 3.7% at biweek 14-15.
• Overnight, there was a greater median percentage of time between 63 and 54 mg/dL than during the day.
• Throughout the entire pregnancy, there were 1-4 hypoglycemic incidents every two weeks, however, they considerably decreased after the 20th week and mostly happened during the day.
• From 12 to 3 am during the overnight period, there were increased hypoglycemic and event occurrences.
• Four subjects (16%) experienced seven protracted hypoglycemic bouts, mostly over the course of one night, without any concomitant severe hypoglycemia(SH). A single episode of SH was experienced by three subjects.

The authors concluded that in pregnancies complicated by type 1 diabetes, there was a substantially greater risk of hypoglycemia throughout pregnancy during the nocturnal period with a persistent daily risk of hypoglycemic episodes.

REFERENCE

Kaur RJ, Smith BH, Ozaslan B, Pinsker JE, Trinidad MC, O'Malley G, Desjardins D, Castorino KN, Levister C, Reid C, McCrady-Spitzer S, Ogyaadu SJ, Church MM, Piper M, Kremers WK, Rosenn B, Doyle FJ 3rd, Dassau E, Levy CJ, Kudva YC. Hypoglycemia in Prospective Multicenter Study of Pregnancies with Pre-Existing Type 1 Diabetes on Sensor-Augmented Pump Therapy: The LOIS-P Study. Diabetes Technol Ther. 2022 Aug;24(8):544-555. doi: 10.1089/dia.2021.0479. PMID: 35349353; PMCID: PMC9353990.