Continuous Glucose Monitoring in Pregnancy: Importance of Analyzing Temporal Profiles to Understand Clinical Outcomes
Authors: Scott Eleanor M. , Feig Denice S. , Murphy Helen R. , Law Graham R. ,   The CONCEPTT Collaborative Group, Murphy Helen , Grisoni Jeannie , Byrne Carolyn , Neoh Sandra , Davenport Katy , Donovan Lois , Gougeon Claire , Oldford Carolyn , Young Catherine , Amiel Stephanie , Hunt Katharine , Green Louisa , Rogers Helen , Rossi Benedetta , Feig Denice , Cleave Barbara , Strom Michelle , Corcoy Rosa , de Leiva Alberto , Adelantado Juan María , Chico Ana Isabel , Tundidor Diana , Keely Erin , Malcolm Janine , Henry Kathy , Morris Damian , Rayman Gerry , Fowler Duncan , Mitchell Susan , Rosier Josephine , Temple Rosemary , Turner Jeremy , Canciani Gioia , Hewapathirana Niranjala , Piper Leanne , McManus Ruth , Kudirka Anne , Watson Margaret , Bonomo Matteo , Pintaudi Basilio , Bertuzzi Federico , Corica Giuseppina Daniela , Mion Elena , Lowe Julia , Halperin Ilana , Rogowsky Anna , Adib Sapida , Lindsay Robert , Carty David , Crawford Isobel , Mackenzie Fiona , McSorley Therese , Booth John , McInnes Natalia , Smith Ada , Stanton Irene , Tazzeo Tracy , Weisnagel John , Mansell Peter , Jones Nia , Babington Gayna , Spick Dawn , MacDougall Malcolm , Chilton Sharon , Cutts Terri , Perkins Michelle , Scott Eleanor , Endersby Del , Dover Anna , Dougherty Frances , Johnston Susan , Heller Simon , Novodorsky Peter , Hudson Sue , Nisbet Chloe , Ransom Thomas , Coolen Jill , Baxendale Darlene , Holt Richard , Forbes Jane , Martin Nicki , Walbridge Fiona , Dunne Fidelma , Conway Sharon , Egan Aoife , Kirwin Collette , Maresh Michael , Kearney Gretta , Morris Juliet , Quinn Susan , Bilous Rudy , Mukhtar Rasha , Godbout Ariane , Daigle Sylvie , Solomon Alexandra Lubina , Jackson Margaret , Paul Emma , Taylor Julie , Houlden Robyn , Breen Adriana , Banerjee Anita , Brackenridge Anna , Briley Annette , Reid Anna , Singh Claire , Newstead-Angel Jill , Baxter Janet , Philip Sam , Chlost Martyna , Murray Lynne , Castorino Kristin , Jovanovic Lois , Frase Donna , Mergler Sonya , Mangoff Kathryn , Sanchez Johanna , Klein Gail , Ruedy Katrina , Kollman Craig , Lou Olivia , Pragnell Marlon 
Published: March 2020

OBJECTIVE
To determine if temporal glucose profiles differed between 1) women who were randomized to real-time continuous glucose monitoring (RT-CGM) or self-monitored blood glucose (SMBG), 2) women who used insulin pumps or multiple daily insulin injections (MDIs), and 3) 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).

RESEARCH DESIGN AND METHODS
Standard summary metrics and functional data analysis (FDA) were applied to CGM data from the CONCEPTT trial (RT-CGM, n = 100; SMBG, n = 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.

RESULTS
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.

CONCLUSIONS
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.