Prenatal Hair Cortisol Concentrations during the COVID-19 Outbreak: Associations with Maternal Psychological Stress and Infant Temperament

BACKGROUND: Maternal psychological stress during pregnancy, including stress resulting from disasters and trauma, has been linked to temperamental difficulties in offspring. While heightened cortisol concentrations are often hypothesized as an underlying mechanism, evidence supporting this mechanism is inconsistent. To address these issues, this preregistered study investigated the following associations between: 1) prenatal psychological stress and hair cortisol, as a biomarker for chronic stress, during the COVID-19 outbreak (i.e., as a worldwide psychological stressor), and 2) maternal hair cortisol during the COVID-19 outbreak and later infant temperamental negative affectivity and orienting/regulation. Additionally, we explored whether associations were different for women with low versus high socioeconomic status (SES) and at different stages of pregnancy. METHOD: Pregnant women (N =100) filled out online questionnaires during the first COVID-19 lockdown. Maternal hair samples were collected during home visits. When infants were six months old, mothers reported on their infant’s temperament. RESULTS: While analyses revealed no associations between prenatal COVID-19 psychological stress and hair cortisol during the COVID-19 outbreak, SES proved to be a moderator in this association. Only pregnant women with higher levels of SES, showed a positive association between work-related and social-related COVID-19 worries and hair cortisol. Finally, prenatal hair cortisol was not associated with later infant temperamental negative affectivity and orienting/regulation. CONCLUSION: While the COVID-19 outbreak proved to be a major psychological stressor, the physiological impact of the crisis might be different for pregnant women with higher SES as compared to lower SES.