Maternal stress during pregnancy is more than just a short-term concern — it can leave a lasting imprint on offspring, too.
A recent study from scientists in Germany looked at macaques, a type of monkey, and discovered that stress hormones during the first half of pregnancy can have a profound impact on how the offspring develop, going so far as to alter their stress response for years to come.
The study focused on how the pregnant mother’s exposure to environmental stress, like food shortages or social conflict, affected the growth of the hypothalamic-pituitary-adrenal, or HPA, axis, a key player in deciding how organisms cope with stress.
The researchers observed these macaques over nine years, collecting fecal samples to measure glucocorticoid metabolites, a marker that indicates stress hormone levels. The findings were striking: Early prenatal stress was linked to heightened HPA-axis activity in the offspring, with effects that lasted well into adulthood.
Notably, stress experienced later in the macaques’ pregnancy or even after birth did not appear to have the same long-term effects. That highlights a crucial window for fetal growth when environmental conditions can set the stage for health outcomes across the offspring’s entire lifespan.
Previous research has shown that early maternal stress can contribute to altered growth, immune system changes, and even gut microbiome troubles.
Of course, these are monkeys, not people. But the findings showcase the importance of timing in prenatal stress and its far-reaching impacts on health, suggesting that even small stressors can have a big impact.