Catecholamine and cortisol reaction to childbirth

One way to study the stressfulness of childbirth is to examine the output of stress hormones. In this study, urinary catecholamines and salivary cortisol from 50 primiparous women were collected for 1 day during gestational weeks 37 to 39, hourly during labor and delivery, and 2 hr and 2 days postpartum. All three stress hormones increased statistically significantly from pregnancy to labor. The increase in adrenaline and cortisol was more than 500%, and the increase in noradrenaline was about 50%. After labor, the output decreased but not statistically significantly below the levels during late pregnancy. Hormone levels during late pregnancy, during labor and delivery, and during the period postpartum mostly did not correlate systematically. However, noradrenaline and adrenaline, as well as adrenaline and cortisol, were positively correlated during labor. After administration of epidural analgesia, there was a moderate but significant decrease in noradrenaline and adrenaline, whereas cortisol did not change. In conclusion, the results of this study support the assumption that childbirth is a very stressful event and that the stress responses vary considerably among women. The substantial increase of adrenaline and cortisol compared with noradrenaline indicates that mental stress is more dominant than physical stress during labor.