Continuous Glucose Monitoring in Pregnancy: Importance of Analyzing Temporal Profiles to Understand Clinical Outcomes.

Abstract

To determine if temporal glucose profiles differed between <i>1</i>) women who were randomized to real-time continuous glucose monitoring (RT-CGM) or self-monitored blood glucose (SMBG), <i>2</i>) women who used insulin pumps or multiple daily insulin injections (MDIs), and <i>3</i>) women whose infants were born large for gestational age (LGA) or not, by assessing CGM data obtained from the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT). Standard summary metrics and functional data analysis (FDA) were applied to CGM data from the CONCEPTT trial (RT-CGM, <i>n</i> = 100; SMBG, <i>n</i> = 100) taken at baseline and at 24- and 34-weeks' gestation. Multivariable regression analysis determined if temporal differences in 24-h glucose profiles occurred between comparators in each of the three groups. FDA revealed that women using RT-CGM had significantly lower glucose (0.4-0.8 mmol/L [7-14 mg/dL]) for 7 h/day (0800 h to 1200 h and 1600 h to 1900 h) compared with those with SMBG. Women using pumps had significantly higher glucose (0.4-0.9 mmol/L [7-16 mg/dL]) for 12 h/day (0300 h to 0600 h, 1300 h to 1800 h, and 2030 h to 0030 h) at 24 weeks with no difference at 34 weeks compared with MDI. Women who had an LGA infant ran a significantly higher glucose by 0.4-0.7 mmol/L (7-13 mg/dL) for 4.5 h/day at baseline, by 0.4-0.9 mmol/L (7-16 mg/dL) for 16 h/day at 24 weeks, and by 0.4-0.7 mmol/L (7-13 mg/dL) for 14 h/day at 34 weeks. FDA of temporal glucose profiles gives important information about differences in glucose control and its timing, which are undetectable by standard summary metrics. Women using RT-CGM were able to achieve better daytime glucose control, reducing fetal exposure to maternal glucose.