j. Perinat. Med. Plasma immunoreactive beta-endorphin, ACTH and cortisol concen- 15 (1987) 45 trations in mothers and their neonates immediately after delivery — their relationship to the duration of labor

Childbirth certainly ranks among the most stressful physiological events in the life of women in the reproductive age. During labor there exists a variety of maternal Stressors ranging from the intensely physical'one of labor per se to the perceptive of pain associated with labor and to the psychological Stressors of antenatal anxiety or anticipated joy of the expected baby. As to the infant, its major Stressors during labor will probably be periods of hypoxia and mechanical trauma. Whether the fetus in parturition feels pain, which could contribute to reactive changes in its hormonal balance, remains for the time being, an open question [12]. The body responds to increased physical and psychological demands by increased release of hormones (such as ACTH and beta-endorphin chiefly from the anterior pituitary and cortisol from the adrenal cortex) into the blood stream [2, 6, 7, 11, 14]. These hormones serve to adapt the body — prominently its cardiovascular, energy-providing and perceptive systems — to the stress situation. They induce rapid and potent responses from the cell groups to be activated and can play an important role in preventing organic damages caused by extraordinary requirements to the body.