Maternal and fetal endocrine stress response at vaginal delivery with and without an epidural block.

Maternal and fetal stress response at vaginal delivery were studied in 19 normal parturients at term. Ten patients to whom an epidural block (group EA) had been administered were compared with 9 patients (group NEA) who used only nitrous oxide for pain relief. Plasma concentrations of ACTH, cortisol, 17-alpha-hydroxyprogesterone, blood glucose and catecholamines were measured in maternal and umbilical vein blood at delivery and in maternal vein blood 30 minutes after delivery. At delivery maternal plasma concentrations of ACTH, cortisol and catecholamines were lower in the EA group compared with in the NEA group. There were no differences in umbilical plasma concentrations of the studied stress variables between the two groups. A linear relation was demonstrated between maternal and umbilical vein cortisol concentration. In both the EA and NEA group a significant fall in ACTH, 17-alpha-hydroxyprogesterone and catecholamine concentrations were demonstrated 30 minutes after delivery, whereas cortisol and blood glucose were virtually unchanged. It was found that epidural anesthesia reduced the maternal stress hormones at delivery but seemed to have little or no effect on the fetal endocrine stress hormones.