Cortisol levels in human pregnancy in relation to parity and age.

Data are presented of a study on the relationship between cortisol, amenorrhea, parity, and age among pregnant women. Total cortisol concentrations were measured by a radioimmunoassay in healthy pregnant women (n = 527), including 105 nulliparas and 422 multiparas. The serum concentration of total cortisol increased linearly with progression of amenorrhea. Significantly higher cortisol levels were found in nulliparas compared to multiparas and independent of amenorrhea. Since parity and age are strongly correlated, age-dependent changes may contribute to the difference in cortisol level between nulliparas and multiparas. Analysis of the age-dependent changes on this difference in cortisol level showed no significant influence.