Association between fasting plasma glucose at diagnosis and large-for-gestational-age in Japanese women with gestational diabetes mellitus: Hamamatsu GRACE Study 6

Abstract

Maternal high fasting plasma glucose (FPG) is a well-known risk factor for large-for-gestational-age (LGA) infants. However, this association remains unclear among Japanese women with gestational diabetes mellitus (GDM). Therefore, we examined this issue in Japanese women with GDM, accounting for body mass index (BMI). This retrospective study analyzed 543 Japanese women with GDM and evaluated the associations of 1-standard deviation (SD) increments in fasting, 1-hour, and 2-hour plasma glucose and HbA1c levels with LGA. LGA was defined as birth weight above the 90th percentile for gestational age. Multivariable logistic regression was used to estimate ORs and 95% CIs for LGA per 1-SD increment in fasting, 1-hour, and 2-hour plasma glucose and HbA1c. Model 1 was adjusted for maternal age, smoking, family history of diabetes, insulin use, parity, gestational age at delivery, gestational age at diagnosis, and gestational weight gain; Model 2 was additionally adjusted for pre-pregnancy BMI. The prevalence of LGA was 9.6%. In model 1, the FPG was independently and positively associated with LGA (adjusted OR 1.44, 95% CI: 1.07–1.94). The area under the receiver operating characteristic (ROC) curve for FPG in discriminating LGA was 0.692, with an optimal cutoff of 86.0 mg/dL. After additional adjustment for pre-pregnancy BMI (model 2), FPG was no longer associated with LGA. Other glycemic parameters were not associated with low birth weight, small-for-gestational-age, or LGA. FPG at GDM diagnosis may provide limited discriminatory information for LGA. However, its association with LGA was attenuated after adjustment for pre-pregnancy BMI.