Parity does not alter baseline or stimulated activity of the hypothalamus-pituitary-adrenal axis in women.

Pregnancy is associated with considerable physiological adaptations, some of which long outlast the state of pregnancy. Although it is well documented that pregnancy produces alterations of the hypothalamus-pituitary-adrenal axis, the longer-term effects of pregnancy on this system have not been systematically examined in humans. Subjects in the present study were 159 nulliparous and 265 parous women. Data analysis revealed no impact of parity on baseline activity (salivary cortisol: response to awakening, F </= .03, day profile: F </= 3.89, both n.s.). In a subsample, similar results were obtained for dexamethasone-suppressed salivary cortisol levels (all F </= 1.45 n.s., n = 45), as well as salivary cortisol, total cortisol, and ACTH responses to stimulation with a psychosocial stress protocol (all F </= .93 n.s., n = 47). These findings suggest that parity is not associated with long-term alterations of hypothalamus-pituitary-adrenal axis activity, and postpregnancy measures can, therefore, be used as proxy markers for a woman's prepregnancy status of this system. (c) 2006 Wiley Periodicals, Inc.