Objective: Both self-reported indicators of stress and hormones such as cortisol and corticotrophin-releasing hormone (CRH) have been examined in relation to preterm birth. Although these hormones have been interpreted as biomarkers of stress, it is unclear whether psychosocial measures are empirically associated with biomarkers of stress in pregnant women.
Methods: We analyzed data from 1,587 North Carolina pregnant women enrolled in the Pregnancy, Infection,and Nutrition study during 2000-2004 who provided at least one saliva sample for cortisol measurement or blood samples for CRH at 14-19 and 24-29 weeks' gestation. Cortisol measures were limited to those taken between 8 and 10 a.m. Perceived stress, state-trait anxiety, coping style, life events, social support, and pregnancy-specific anxiety were measured by questionnaires and interviews. Spearman correlations and multiple regressions were used to describe the relationship among the measures of stress.
Results: No correlations larger than r = 0.15 were seen between reported psychosocial measures and cortisol or CRH. Women with demographic characteristics associated with poor pregnancy outcomes (unmarried, African-American, young, low pre-pregnancy body mass index) reported higher levels of stress but did not consistently have higher levels of stress hormones. Pre-eclampsia was associated with higher CRH, but not with higher cortisol.
Conclusions: The relationship between measurements of reported stress and biomarkers is not straightforward in large epidemiological studies of pregnancy.