Prolonged maternal glucocorticoid exposure during late gestation in sheep and rodents is associated with reduced mitochondrial oxidative phosphorylation capacity and biogenesis in fetal tissues, compared to short-term physiological glucocorticoid exposure.

When a mother has too much stress hormone for too long during late pregnancy, the baby's cells receive a signal that overactivates their energy-producing factories. This causes the factories to grow too early and become inefficient, reducing their ability to make energy. The stress hormone directly turns on genes inside the mitochondria and also triggers another hormone that further boosts this process, but too much of both leads to damaged energy production.