Chemical and Medicinal Impacts of Gestational Diabetes Mellitus on Heart Rate Variability Indices-A Case-Control Study

Background: Gestational diabetes [GDM] is one of the most common metabolic disorders associated with many adverse maternal and fetal complications including cardiovascular events. This study aimed to evaluate the function of the autonomic nervous system by heart rate variability [HRV] between pregnant women with GDM and healthy pregnant women. Methods: The study was a case-control observational study on 50 pregnant women with GDM and 51 healthy pregnant women. They were assigned to the study at 32-36 weeks of gestational age. Demographic and past medical history and lab findings were gathered. HRV was assessed by a time-domain analysis of 24-hour cardiac Holter monitoring including SDNN-SDANN-rMSSD and pNN50 variables. Results: The mean age of the participants was 28.69 [± 5.5]. Data analysis showed no significant difference in the age [p-value: 0.10], maternal hypothyroidism [p-value: 0.2], and PCO [p-value: 1/000] between two groups. There was no significant difference between SDNN [p-value: 0.21], SDANN [pvalue: 0.11], and rMSSD [p-value: 0.87] between two groups. pNN50 in GDM group decreased significantly [P-value = 0.0001]. Conclusion: A significant decrease in the pNN50 index in GDM group may be a marker of autonomic dysfunction. Reduced pNN50 could be explained by decreasing parasympathetic activity and sympathetic overcome in pregnancy, especially in pregnancy associated with diabetes, leading to instability of the autonomic nervous system.