High levels of human chromogranin A in umbilical cord plasma and amniotic fluid at parturition

OBJECTIVE: The human placenta is a neuroendocrine organ that produces several hypothalamic and pituitary hormones that are secreted during pregnancy and parturition into maternal and fetal circulation and amniotic fluid. Human chromogranin A (CgA) is a glycoprotein mainly localized to the adrenal medulla and released in response to several stressful events. During pregnancy, intrauterine tissues express and synthesize CgA mRNA and peptide and secret it into the biologic fluids of pregnancy, so we investigated whether maternal, umbilical, and amniotic human CgA levels are affected by the stress of parturition. METHODS: We measured pregnancy CgA levels in maternal and umbilical cord plasma and in amniotic fluid at term (39-40 weeks), by enzyme-linked immunosorbent assay at elective cesarean (n = 16), after spontaneous vaginal delivery (n = 12), and longitudinally throughout labor and 2 hours postpartum. RESULTS: CgA levels were highest in umbilical cord blood (P <.001). Umbilical cord plasma and amniotic fluid CgA levels were significantly higher at spontaneous vaginal delivery than at cesarean (P <.001), and the levels were not changed in maternal plasma according to cervical dilatation and postpartum. CONCLUSIONS: The present findings showed that the stress of parturition increased CgA levels in umbilical cord plasma and amniotic fluid and was probably of fetal origin. Whatever the mode of delivery, CgA levels in infants were much more elevated than in mothers, providing evidence for an unusual and sustained high level of sympathoadrenal stimulation in full-term neonates.