Plasma epinephrine, norepinephrine, and cortisol of multigravidas in pregnancy and labor and in umbilical cord arteries after delivery

Plasma epinephrine, norepinephrine and cortisol levels were determined for 61 full-term multigravidas in last trimester pregnancy and during three phases of labor: 3-4 cm (Phase 1), 7 cm (Phase 2), and 10 cm (Phase 3) cervical dilatation. Maternal venous and cord arterial samples were obtained after delivery (Phase 4). Epinephrine shows significant increases in the mean and variance from pregnancy through Phases 1-3 of labor. Cortisol levels rise significantly in every phase of labor. Norepinephrine levels increase significantly only after delivery. Multigravidas, compared to primigravidas, had significantly higher prenatal norepinephrine levels, higher post-delivery epinephrine levels, and lower cortisol levels at every data collection period. Norepinephrine and cortisol, but not epinephrine, showed moderate correlations between pregnancy and labor, and moderate to high intercorrelations in labor, suggesting consistency in subject status for the repeated measures. All cord arterial measures are lower and uncorrelated to the Phase 4 maternal samples. After analgesia and epidural anesthesia, maternal levels of epinephrine in Phase 3 are significantly decreased. The results show that catecholamines and cortisol vary with parity, phase of labor, analgesia and epidural anesthesia.