To investigate the relationship of maternal anxiety to the progress in labor, we assayed 218 samples of plasma catecholamines from 43 women irr labor by high performance liquid chromatography and compaired plasma catecholamines with the progress in labor, uterine activity (Montevideo unit) and the State-Trait Anxiety Inventory (STAI), 1) In the different stages of labor the levels of plasma norepinephrine (n==!15) and epinephrine (n=;16) were as follows. In the second stage, the plasma norepinephrine