Relationship Between Maternal Serum Cortisol and Maternal Insulin Resistance and Fetal Ultrasound Characteristics in Gestational Diabetes Mellitus

Introduction: Cortisol is proven to play a crucial role in hyperglycemia and fetal development in gestational diabetes mellitus (GDM). This research aims to investigate the relationship between maternal serum cortisol and insulin resistance indices and fetal ultrasound characteristics in women with GDM. Methods: A cross-sectional and descriptive study on 144 GDM in Vietnam from January 2015 to December 2020. Serum cortisol was measured using electrochemiluminescence immunoassay at 8 a.m. on the examination day in the vicinity of the 24th gestational week. Fetal ultrasound was performed by an experienced person who was blind to the study. Results: The mean cortisol level in the GDM group was 627.04 nmol/L. Serum cortisol levels positively correlated with abdominal circumference (AC), fasting plasma glucose (FPG), insulin, triglycerides, HOMA2-IR, and Mathew indices (with r of 0.18, 0.22, 0.18, 0.17, 0.18, and 0.22, respectively). Serum cortisol levels negatively correlated with QUICKI and McAuley indices (with r of -0.19 and -0.21), respectively. In a univariate linear regression, maternal serum cortisol positively correlated with fetal AC, head circumference (HC), and biparietal diameter (BPD) (with r of 0.21; 0.23; and 0.25, respectively). In a multivariate linear regression analysis, cortisol positively correlated with fetal AC, HC, and BPD after adjusting to maternal McAuley index. Conclusion: Serum cortisol levels in GDM correlated with fasting blood glucose, triglycerides, and insulin resistance. Besides, serum cortisol levels in GDM positively correlated with fetal development.