Increased pituitary-adrenal activation and shortened gestation in a sample of depressed pregnant women: a pilot study.

Background: Major depression (MD) is frequently accompanied by a relatively increased production of the stress hormone cortisol. During pregnancy corticotrophin releasing hormone (CRH) is secreted from the placenta and critically high levels of CRH are one of the key triggers for parturition. Maternal cortisol promotes the secretion of placental CRH. In this study, we examined the hypothesis that women suffering with MD in pregnancy would have relatively increased cortisol secretion, a time-advanced rise in placental CRH production and an earlier delivery of the baby.

Methods: A group of medication-free pregnant women, free of know obstetric and medical complications, with (n=27) and without (n=38) MD were recruited. Blood concentrations of CRH, adrenocorticotrophic hormone (ACTH) and diurnal salivary cortisol concentrations were measured at fixed time points.

Results: Maternal cortisol concentrations were highly correlated with placental CRH secretion for the entire group. Second trimester CRH concentrations and mean evening salivary cortisol concentrations were significantly higher in the depressed women. Although pregnancy length was shorter in the depressed women there were no statistical relationships between the stress hormone measures and pregnancy length.

Limitations: The sample size was small and highly selected.

Conclusions: These findings suggest that depressed pregnant women hypersecrete cortisol in a diurnal pattern similar to that typical of MD, and that this leads to a time-advanced rise in placental CRH secretion. Factors other than this stress-delivery mechanism may be contributing to the shortened pregnancy length in depressed women.