Evaluation of an association between maternal prenatal psychological stress and insulin resistance during pregnancy and postpartum

Various physiological mechanisms counteract insulin resistance (IR) during normal pregnancy. Psychological stress is a known, independent risk factor for developing IR. Pregnancy-specific psychological stress may cause IR and increase the risk of overt diabetes. Hence, the study aims to evaluate maternal psychological stress using multiple stress markers and their association with changes in IR during pregnancy and postpartum. Anthropometric measurements such as height, weight and skinfold thickness were measured using standard techniques. The stress markers were assessed using perceived stress scales (K10 questionnaire), a physiological marker of stress (Heart rate variability [HRV] measures) and biochemical stress markers (Saliva, hair cortisol levels). IR was estimated using homeostasis model assessment-estimated IR (HOMA-IR). The association of stress markers with IR was studied among fifty healthy pregnant women during pregnancy and postpartum. The psychological stress scores and saliva cortisol were significantly higher during pregnancy than postpartum (P = 0.000). A comparison of cardiac autonomic function as assessed by HRV measures shows that high frequency in normalised units (HFnu) was significantly higher during the postnatal period than in the prenatal period (P = 0.000). High frequency (HF) spectral power in absolute units was also significantly higher (P = 0.002) in the postpartum period (2612.30 ± 432.24) when compared with the prenatal period (1446.10 ± 299.15). Low frequency in normalised units (LFnu), low frequency (LF)/HF ratio was significantly higher during the prenatal period than in the postnatal period (P = 0.000). As assessed by HOMA-IR values, IR was significantly higher during the prenatal period than postpartum (P = 0.04). There was a significant positive correlation between prenatal psychological stress scores, HRV parameters (LFnu, LF/HF) and postnatal IR. Pregnancy is associated with higher psychological stress levels and IR than postpartum. Furthermore, the maternal cardiac autonomic marker could predict postnatal IR among healthy pregnant women.