Effects of prenatal exposure to maternal cortisol and psychological stress on neonatal development: the GENEIDA mother-infant cohort (Andalusia, Spain)

Several studies have shown that high cortisol levels and psychological stress during pregnancy are associated with adverse outcomes in the offspring, including lower gestational age, and neurodevelopmental delays. This study aimed to evaluate the association of hair cortisol levels and psychological maternal stress during pregnancy with anthropometric measures at birth. Pregnant women were recruited during the first trimester (T1) and followed-up during the second (T2) and third (T3) trimesters, and delivery. Hair samples were collected from the scalp to analyse cortisol levels, while psychological stress and anxiety were assessed through validated instruments during each trimester. From the 800 mother–child pairs participating in the prospective birth cohort < blinded for peer-review > 669 mother–child pairs were selected for this analysis. In males, birth-weight was positively associated with hair cortisol levels (log-10 transformed) during T1 (β = 0.244, 95% CI: 0.028; 0.461, p = 0.027), T2 (β = 0.291, 95% CI: 0.050; 0.531, p = 0.01), and across the entire pregnancy (mean log-10 transformed hair cortisol levels: β = 0.288, 95% CI: 0.007; 0.570, p = 0.01). In females, birth-weight was inversely associated with maternal psychological stress in T1 (β = -0.022, 95% CI: -0.040; -0.003, p = 0.02), while birth length was inversely associated with maternal psychological stress in T2 (β = -0.119, 95% CI: -0.241; 0.003, p = 0.05). Furthermore, maternal anxiety during T3 was associated with an increase in female birth-weight (β = 0.015, 95% CI: 0.002; 0.028, p = 0.02). These findings suggest that elevated hair cortisol levels, along with psychological stress and anxiety during pregnancy, may influence foetal growth and impact on birth anthropometric measurements.