Attenuation of maternal psychophysiological stress responses and the maternal cortisol awakening response over the course of human pregnancy

Abstract

The effects of maternal stress during pregnancy may depend, in part, on the timing in gestation of the occurrence of stress. The aim of the present study was to examine the effect of stage of gestation on maternal psychophysiological responses to stress using a standardized laboratory paradigm and on the cortisol response to awakening (CAR). A longitudinal design was employed to quantify maternal psychophysiological stress reactivity [changes in heart rate (HR), blood pressure, salivary cortisol, and psychological distress in response to the trier social stress test (TSST)] and the CAR at approximately 17 and 31 weeks gestation in a sample of 148 women. To account for the possible effects of habituation when being exposed to the same stress protocol twice, a non-pregnant comparison group (CG, N = 36) also underwent these assessments at two time points, with a comparable time interval between the assessments. In both groups, the TSST elicited significant changes in maternal HR, mean arterial pressure, and psychological distress levels but not a significant increase in cortisol levels. Among the pregnant women (pregnant group(PG)), the stressor-induced increases in HR, blood pressure, and psychological distress were significantly lower at the second (31 weeks gestation) compared to the first (17 weeks gestation) assessment of pregnancy (all p < 0.01). The maternal CAR was also significantly attenuated in later compared to earlier gestation (p = 0.003). In the CG, there were no significant differences in psychophysiological stress responses and in the CAR across the two assessments. Among pregnant women there is a progressive attenuation of psychophysiological stress responses with advancing gestation. This attenuation is unlikely to be attributable to habituation. Individual differences in the degree of attenuation of stress responses over gestation may represent a novel marker of stress susceptibility in human pregnancy.

Keywords::

• Cortisol awakening response (CAR) or rise
• heart rate
• mean arterial pressure
• pregnancy
• psychosocial stress
• Trier Social Stress Test (TSST)

Acknowledgements

This study was supported, in part, by US PHS (NIH) grants HD-33506, HD-041696, and HD-47609 to PDW.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Notes

^† Our final models included all 148 subjects. However, analyses on only the subgroup of subjects that completed both visits (n = 76) provided similar results (significant effects with comparable effect sizes), albeit with reduced statistical power.

^‡ Running the same models for systolic and diastolic blood pressure separately yielded similar results.