Roles of insulin resistance and beta cell dysfunction in macrosomia among Chinese women with gestational diabetes mellitus.

Abstract

The aim was to examine associations of insulin resistance and beta cell dysfunction with macrosomia in Chinese women with gestational diabetes mellitus (GDM). We performed a secondary analysis of 923 women with GDM enrolled in a randomized controlled trial in 2010-2012 in Tianjin, China. Insulin resistance and beta-cell function were estimated using Homeostasis model assessment. Binary logistic regression was used to obtain adjusted odds ratios (ORs) and 95% confidence intervals (CIs). A two-step adjustment scheme was used to control for effects of potential confounders. A total of 138 women (16.5%) had excessive weight gain, 127 (7.3%) had macrosomia and 150 (16.3%) had a large for gestational age (LGA) infant. Compared to women in bottom tertile of insulin resistance, women in upper tertile had increased risk of excessive weight gain (OR: 4.32, 95%CI: 1.95-9.62), macrosomia and LGA (OR: 2.61, 95%CI: 1.20-5.69; 2.75, 95%CI: 1.35-5.62, respectively). The observed overall effects were mainly due to their large effect sizes among women with normal pre-pregnancy body weight. However, beta cell function was not found to be associated with either of them. Increased insulin resistance during pregnancy was associated with excessive weight gain, macrosomia and LGA in Chinese women with GDM.