New Delhi: High levels of maternal stress hormones during early pregnancy may have lasting effects on children's health, according to a long-term study on wild Assamese macaques in Thailand. Published in the Proceedings of the Royal Society B, the research offers critical insights into how early developmental stages influence the stress system under natural environmental conditions.
Conducted by researchers from the University of Gottingen and the German Primate Center – Leibniz Institute for Primate Research in Germany, the study observed stress effects on offspring up to 10 years of age. The findings are particularly relevant for humans, as early pregnancy stress has been linked to long-term health issues, including increased risks of stress disorders and immune problems.
The study highlights the role of the hypothalamic-pituitary-adrenal (HPA) axis, a central system for coping with stress. Researchers found that exposure to maternal glucocorticoids during early pregnancy significantly affects the HPA axis. This critical period coincides with the early phase of organ differentiation in the first half of pregnancy.
“Our research indicates that the timing of maternal stress hormone exposure during and after pregnancy has a significant impact on the development and health of the offspring,” said Oliver Schulke, a scientist involved in the study. “Even moderate environmental changes, rather than catastrophic events, can trigger these effects.”
Interestingly, elevated stress hormones later in pregnancy or after birth did not produce the same outcomes. This suggests that preventive measures to mitigate long-term health risks should focus on specific timing during pregnancy.
Unlike laboratory studies, this research observed monkeys in their natural habitat over nine years. Pregnant females’ fecal samples were collected repeatedly to measure glucocorticoid metabolite levels. These measurements reflected environmental stressors like food scarcity, temperature changes, and social interactions. The stress hormone levels of the offspring were then tracked from infancy to adulthood.
The results revealed that stress-induced changes in the offspring's stress axis persisted through their juvenile years and into adulthood at nine to ten years of age.
“This study helps identify critical periods and mechanisms for intervention to reduce the long-term health risks associated with early pregnancy stress,” Schulke added. The findings underscore maternal stress's profound and lasting impact on offspring development.