TOPLINE:
In women with gestational diabetes (GD), continuous glucose monitoring (CGM) shows elevated glycemic metrics earlier in pregnancy compared with the standard oral glucose tolerance test (OGTT).
METHODOLOGY:
- Earlier diagnosis and treatment of GDM may mitigate some perinatal risks, but the traditional OGTT at 24-28 weeks’ gestation delivers inconsistent results in early pregnancy, potentially leading to missed cases or overdiagnosis.
- This prospective noninterventional observational study conducted at two US academic-based clinical sites from June 2020 to December 2021 assessed CGM-derived glycemic patterns in 768 participants (mean age, 33 years; 77% White) enrolled prior to 17 weeks’ gestation with singleton pregnancy and an initial A1c level < 6.5%.
- Participants were encouraged to wear a blinded Dexcom G6 Pro CGM System sensor continuously until the day of delivery, with a median CGM wear duration of 67 days prior to OGTT.
- GDM was diagnosed using an OGTT conducted between 24 and 34 weeks’ gestation, which sorted women into those with GDM (n = 58) or without GDM (n = 710).
- CGM-derived glycemic patterns were compared between the participants with and without GDM.
TAKEAWAY:
- Women with GDM had a higher mean glucose (109 ± 13 vs 100 ± 8 mg/dL; P < .001) and greater glucose SD (23 ± 4 vs 19 ± 3; P < .001) than those without GDM throughout the gestational period prior to OGTT.
- Women with GDM spent lesser time in glycemic ranges of 63-140 mg/dL (87% ± 11% vs 94% ± 4%; P < .001) and 63-120 mg/dL (70% ± 17% vs 84% ± 8%; P < .001) throughout gestation than those without GDM prior to OGTT.
- The daytime and overnight mean glucose levels were higher in those with vs without GDM and attributed to increased hyperglycemia rather than decreased hypoglycemia, with those with GDM spending more time > 120 mg/dL and > 140 mg/dL and less time < 63 mg/dL and < 54 mg/dL.
- Mean glucose and percent time in the > 120 mg/dL and > 140 mg/dL ranges were higher in those with GDM as early as 13-14 weeks of gestation, which persisted at each 2-week period prior to OGTT.
IN PRACTICE:
“CGM could be used in addition to or instead of OGTT to screen individuals at risk for hyperglycemia during pregnancy, even as early as the first trimester,” the authors wrote, adding that “CGM could potentially play a pivotal role in providing timely identification of distinct glycemic patterns indicative of early dysglycemia.”
SOURCE:
The study, led by Celeste Durnwald, MD, Maternal-Fetal Medicine Research Program, Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, was published online in Diabetes Care.
LIMITATIONS:
To include participants with possible early GDM, the study allowed the inclusion of up to 14 days of CGM data after OGTT in the overall gestational period and up to 10 days in the first and second trimesters. A detailed analysis of glycemia at the earliest timepoint of pregnancy could not be conducted as the first trimester data were limited. The findings may not be generalizable to a population with gestational hyperglycemia, as only 58 participants were identified with GDM using OGTT.
DISCLOSURES:
The study was supported by the Leona M. and Harry B. Helmsley Charitable Trust and UnitedHealth Group. Some authors reported performing advisory work, receiving research support and consultancy fees, and being on scientific advisory boards through their employer, while several authors reported that their institution received funds on their behalf from various pharmaceutical, healthcare, and medical device companies.
A version of this article first appeared on Medscape.com.