Elevated Metabolic Score for Insulin Resistance During Early Midpregnancy Predicts Higher Risk of Gestational Diabetes Mellitus: a Prospective Cohort Study

Purpose: To evaluate the clinical implication of metabolic score for insulin resistance (METS-IR) during early midpregnancy on subsequent risk of gestational diabetes mellitus (GDM) in Chinese women. Methods: : A total of 1747 pregnant women without pre-existing diabetes from the Tongji Maternal and Child Health Cohort (TMCHC) were included in this analysis. Blood glucose and lipid profiles (triglyceride [TG], total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C] and low-density lipoprotein cholesterol [LDL-C]) were measured during 15-19 weeks and 75-g 2-h oral glucose tolerance test was conducted during 24-28 weeks to diagnose GDM. METS-IR was calculated by a modified formula which originally as follows: Ln(2×FPG[mg/dl]+TG[mg/dl])×BMI[kg/m 2 ] /Ln(HDL-C[mg/dl]). Results: : The median (interquartile range) of age was 28 (26-30) years, and 19.7% of them were underweight and 11.7% were overweight/obese before pregnancy. The overall incidence of GDM was 9.4% and median (interquartile range) of METS-IR was 27.36 (24.57-31.07). The median METS-IR was significantly increased with the increasing pre-pregnancy BMI categories (22.92 vs 27.72 vs 35.55, P ＜0.001). Based on quartiles of METS-IR in women with normal pre-pregnancy BMI, participants were classified into 4 groups. Compared with women in the lowest quartile of METS-IR (＜25.52) , the adjusted RRs (95% CIs) of GDM were 2.15 (1.23-3.74), 1.34 (0.72-2.49), and 3.63 (2.22-5.95) for women in quartile 2 (25.52-27.71), quartile 3 (27.72-30.39) and quartile 4 (≥30.40) after adjusting potential confounds. In addition, a significant increase risk of GDM (adjusted RR [95% CI]: 2.55 [1.83-3.55]) was found in women within the highest quartile of METS-IR (≥30.40) compared to the other 3 lower quartiles (＜30.40). Conclusions: : Women with METS-IR (≥30.40) during early midpregnancy were more likely to develop GDM, thus the index might be a reliable early indicator for identifying women at high risk of GDM.