Vertebrate species, including humans, exposed to stress prenatally tend to have higher stress hormones after birth, according to a new Dartmouth-led study published in Scientific Reports. While previous research has reported examples of maternal stress experience predicting offspring stress hormones in different species, this study is the first to empirically demonstrate the impact of prenatal stress on offspring stress hormone levels using data from all known studies across vertebrates.
Through a meta-analysis of 114 results from a total of 39 observational and experimental studies across 14 vertebrate species, including birds, snakes, sheep and humans, the study examines the impact of prenatal exposure to maternal stress on offspring. The researchers analyzed the role of the hypothalamic pituitary adrenal (HPA)-axis, the stress physiological system that is shared across all vertebrates, which ultimately, results in the production of stress hormones known as “glucocorticoids.” The HPA-axis is the hormonal system responsible for mobilizing an animal’s stress response. Offspring exposed prenatally to maternal stress were found to have more stress hormone levels (glucocorticoids) after birth. This could reflect a biological adaptation with an evolutionary history, as more stress hormones could increase an animal’s chances for survival in a stressful environment.