Preterm delivery as a predictor of diurnal cortisol profiles in adulthood: Evidence from Cebu, Philippines

Objectives: Fetal exposure to elevated maternal cortisol can permanently modify hypothalamic-pituitary-adrenal (HPA) axis function, and thereby have long-term health impacts. Maternal cortisol steadily increases throughout normal pregnancy, but is abnormally high in preterm deliveries (<37 weeks). Prematurity remains a widespread public health problem, yet little is known about its potential long-term effects on adult HPA function. Here we test the hypothesis that diurnal cortisol profiles measured in young adulthood will vary based upon an individual's preterm status. Methods: Diurnal salivary cortisol profiles, a marker of HPA-axis function, were measured in 1,403 young adults (ages 21-23 years) participating in the Cebu Longitudinal Health and Nutrition Survey, located in Metropolitan Cebu City, Philippines. Results: Males who had been born preterm exhibited lower morning cortisol and non-significantly elevated evening cortisol, resulting in a more adverse, flatter rate of decline across the day. In contrast, there were no significant differences by preterm status in cortisol measured at any time of day in females. Conclusions: These findings point to potential long-term effects of having been born preterm on adult HPA-axis function, and add to evidence from this and other populations for sex differences in the biological and health impacts of prenatal stress exposure. Am. J. Hum. Biol. 26:598-602, 2014.