Characterizing maternal glycemic control: a more informative approach using semiparametric regression.

Objective: To characterize glucose concentrations measured throughout pregnancy in women with type 1 diabetes using semiparametric regression analysis to examine the gestational time-specific association with fetal outcome. Methods: We conducted a secondary analysis of data from an interdisciplinary program of diabetes in pregnancy of women with type 1 diabetes. Semiparametric regression was used to characterize glucose concentrations measured using reflectance meters throughout pregnancy by examining the time-specific association of maternal glucose with delivery of a large for gestational age (LGA) baby. Results: The optimal model demonstrated that time-specific differences in glycemic profiles of mothers who had LGA versus AGA babies changed at various rates across gestation (p = 0.0007). AGA glucose profiles exceeded LGA profiles in the first trimester and mid pregnancy; conversely LGA glucose profiles exceeded AGA profiles initially during the third trimester. Differences were based on examination of...