Association of insulin resistance and autonomic tone in patients with pregnancy-induced hypertension

Pregnancy-induced hypertension (PIH) remains the main cause of maternal and fatal mortality. Insulin resistance (IR) and autonomic nervous system (ANS) imbalance are two principal drivers of PIH development. Few previous researches investigated the association between IR and ANS imbalance in Chinese PIH patients. 120 pregnant women were enrolled in our study, sixty healthy pregnant women (control group), fourty one gestational hypertension (GH group) and nineteen preeclampsia patients (PE group). The homeostasis model assessment of IR (HOMA-IR) and markers of ANS (plasma biomarkers and heart rate variability (HRV) components) were collected. Body mass index (BMI), Ln(HOMA-IR), noradrenaline level, LnTP (total power), Ln SDNN (standard deviation of the normal-to-normal interval), LnLF (low frequency), LnLF/LnHF (low frequency/high frequency) were different in the GH and PE groups compared with the controls. Significant correlations were observed between Ln (HOMA-IR) and gestational duration (r=0.237, P=0.031), BMI(r=0.314, P=0.002), systolic blood pressure (r=0.108, P=0.016), noradrenaline (r=0.451, P=0.009), LnTP (r=-0.269, P=0.015) and LnLF/HF (r=0.183, P=0.026) in those PIH patients. Furthermore, BMI, noradrenaline and LnTP were independent determinants of Ln(HOMA-IR) in PIH patients by multiple regression analysis. Our finding verified both IR and ANS imbalance were more severe in PIH patients than healthy pregnant women. Moreover, IR had a close association with ANS parameters in PIH patients, suggesting that they probably had contributory effects on the occurrence and development of PIH. We propose that these parameters could be added to the traditional indexes for individualized treatment of PIH patients in the future.