  Psychosocial stress during pregnancy is a known contributor to preterm birth,
but also has been increasingly appreciated as an in utero insult acting
long-term on prenatal and postnatal neurodevelopmental trajectories. These
events impact many information molecules, including both vitamin D and
cortisol. Both have been linked to low birth premature babies. Cortisol tends
to be further elevated in women, while vitamin D tends to be decreased from
their normal levels during pregnancy. One facilitates labor in part by
elevating placental CRH, the other by limiting CRH in placental tissue. Both
are linked to managing adversity. Studies in large animal models with high
resemblance to human physiology are sparse to model the changes induced by such
stress exposure. Using an established pregnant sheep model of stress during
human development, here we focused on measuring the changes in maternal Vitamin
D and cortisol responses due to chronic inescapable stress mimicking daily
challenges in the last trimester of human pregnancy. The present pilot data
show that chronic maternal stress during pregnancy results in endocrine and
metabolic chronic habituation paralleled by sensitization to acute stress
challenges. Chronic stress appears to disrupt a physiological relationship
between oscillations of vitamin D and cortisol. These speculations need to be
explored in future studies.
