Prenatal maternal stress is associated with adverse offspring outcomes, which may be mediated by maternal stress hormones. However, evidence supporting the association between maternal stress and cortisol levels in high-risk pregnancies is limited. This study aims to determine the relationship between self-reported maternal mental distress and maternal salivary cortisol levels in pregnancies complicated by foetal CHD compared with healthy pregnancies.

We recruited women with pregnancies complicated by foetal CHD and healthy pregnancies. Maternal saliva was collected between 22 and 40 gestational weeks. Standardized questionnaires measuring stress, depression, and anxiety were completed by patients. Generalized estimating equation was used to evaluate associations between maternal mental distress scales and cortisol levels.

We studied 165 women (55 CHD, 110 controls) and collected 504 cortisol samples (160 CHD, 344 controls). Women carrying CHD foetuses had higher stress, anxiety, and depression scores compared to women carrying healthy foetuses. However, maternal cortisol levels did not significantly differ in CHD and controls. Cortisol levels were higher in women carrying foetuses with functionally single-ventricle versus two-ventricle CHD. In both CHD and controls, there was no significant association between maternal stress, depression or anxiety scores and cortisol levels.

Our data suggest that self-reported maternal stress, anxiety, and depression are not associated with maternal salivary cortisol levels in CHD and healthy pregnancies. The impact of maternal mental distress on foetal health may be through other mediating pathways other than maternal cortisol concentrations.