Serum cortisol levels of maternal vein, umbilical artery, and umbilical vein classified by mode of delivery.

We measured maternal venous (MV), umbilical arterial (UA), and umbilical venous (UV) cortisol levels of 180 pregnancies at term. The cortisol level of MV was higher than that of UA and UV in all deliveries. The cortisol levels of three samples had no difference between the induced labor group and the spontaneous onset of labor group regardless of delivery mode. In spontaneous vaginal delivery the cortisol levels of three individual samples were significantly higher in primipara than in multipara. The positive correlations were observed in any modes of deliveries between the cortisol levels of MV and UA, and MV and UA and UV. These data suggest that the fetus may produce cortisol by itself and maternal cortisol may inflow to the fetus.