Analysis of Continuous Glucose Monitoring in Pregnant Women With Diabetes: Distinct Temporal Patterns of Glucose Associated With Large-for-Gestational-Age Infants DOI: 10.2337/dc15-0070 OBJECTIVE Continuous glucose monitoring (CGM) is increasingly used to assess glucose con- trol in diabetes. The objective was to examine how analysis of glucose data might improve our understanding of the role temporal glucose variation has on large- for-gestational-age (LGA) infants born to women with diabetes. RESEARCH DESIGN AND METHODS Functional data analysis (FDA) was applied to 1.68 million glucose measurements from 759 measurement episodes, obtained from two previously published ran- domized controlled trials of CGM in pregnant women with diabetes. A total of 117 women with type 1 diabetes (n = 89) and type 2 diabetes (n = 28) who used repeated CGM during pregnancy were recruited from secondary care multidisci- plinary obstetric clinics for diabetes in the U.K. and Denmark. LGA was defined as birth weight ‡90th percentile adjusted for sex and gestational age. RESULTS A total of 54 of 117 (46%) women developed LGA. LGA was associated with lower mean glucose (7.0 vs. 7.1 mmol/L; P < 0.01) in trimester 1, with higher mean glucose in trimester 2 (7.0 vs. 6.7 mmol/L; P < 0.001) and trimester 3 (6.5 vs. 6.4 mmol/L; P < 0.01). FDA showed that glucose was significantly lower midmorn- ing (0900–1100 h) and early evening (1900–2130 h) in trimester 1, significantly higher early morning (0330–0630 h) and throughout the afternoon (1130–1700 h) in trimester 2, and significantly higher during the evening (2030–2330 h) in tri- mester 3 in women whose infants were LGA. CONCLUSIONS FDA of CGM data identified specific times of day that maternal glucose excursions were associated with LGA. It highlights trimester-specific differences, allowing treatment to be targeted to gestational glucose patterns. 1 Division of Epidemiology and Biostatistics, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, U.K. 2 Center for Pregnant Women with Diabetes, De- partments of Endocrinology and Obstetrics, Rig- shospitalet, Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark 3 Elsie Bertram Diabetes Centre, Norfolk and Nor- wich University Hospitals NHS Foundation Trust, Norwich, U.K. 4 Institute of Metabolic Science, University of Cambridge, Cambridge, U.K. Corresponding author: Graham R. Law, g.r.law@ leeds.ac.uk. Received 13 January 2015 and accepted 25 March 2015. This article contains Supplementary Data online at http://care.diabetesjournals.org/lookup/ suppl/doi:10.2337/dc15-0070/-/DC1. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. Graham R. Law, 1 George T.H. Ellison, 1 Anna L. Secher, 2 Peter Damm, 2 Elisabeth R. Mathiesen, 2 Rosemary Temple, 3 Helen R. Murphy, 3 and Eleanor M. Scott 1 Diabetes Care 1 EPIDEMIOLOGY/HEALTH SERVICES RESEARCH Diabetes Care Publish Ahead of Print, published online April 23, 2015