title: Beta-endorphin levels during pregnancy and labor: a role in pain modulation?
abstract: Discovery of the endogenous opiate system of the brain has revolutionized the study of pain and pain management. In this study a convenience sample of 10 pregnant women, 16 nonpregnant women, and 18 men were studied to determine if changes in plasma beta-endorphin-like immunoreactivity affected pain perception during labor. Pregnant women had plasma levels of beta-endorphin significantly higher than nonpregnant women at the midpoint of their menstrual cycle, t = 3.74, df = 31, p = .007. Self-reported pain perception scores were not correlated with plasma beta-endorphin levels. However, as labor progressed, the women reported increased discomfort between contractions and during contractions while beta-endorphin levels increased only slightly. Close examination of the pain pattern indicates that pain perceived by the women between contractions increased at a greater rate than during contractions. This pattern suggests that opiate-active beta-endorphin may increase the ability of women to tolerate acute pain.
authors.affiliation: College of Nursing, University of Arizona, Tucson.
authors.forename: C A
authors.initials: CA
authors.lastname: Cahill
mesh_terms: D005260:Female; D006801:Humans; D007743:Labor, Obstetric / Q000097:blood* / Q000502:physiology; D008297:Male; D008597:Menstrual Cycle; D010146:Pain / Q000097:blood* / Q000502:physiology; D011247:Pregnancy / Q000097:blood* / Q000502:physiology; D012684:Sensory Thresholds; D014590:Uterine Contraction; D001615:beta-Endorphin / Q000097:blood* / Q000502:physiology
chemical_list: D001615:beta-Endorphin