Activin βA in term placenta and its correlation with placental inflammation in parturients having epidural or systemic meperidine analgesia: a randomized study

Study Objective: To investigate the immunohistochemical localization of βA subunit of activin A in human term placenta, as a marker for placental infection/inflammation and elevated temperature, in parturients laboring during two analgesic regimens. Design: Prospective, randomized controlled study. Setting: Delivery room. Patients: 56 healthy, ASA physical status I and II primiparous women in labor. Interventions: Parturients were assigned to receive patient-controlled epidural analgesia (PCEA) with 0.2% ropivacaine or patient-controlled intravenous analgesia PCA with meperidine. Measurements: Histologic and immunohistochemical placental evaluation for white blood cell infiltration and activin βA staining were made. Maternal temperature elevation above 37.6°C and leukocytosis above 15 000/μL were recorded. Main Results: Temperature was not significantly increased in parturients receiving PCEA over those who received (PCA) with meperidine (31% vs 11%, respectively; P = 0.1). There was also no association between temperature elevation during epidural analgesia and increased white blood cell count (>15 000/μL) or presence of polymorphonuclear and/or lymphocyte aggregation in the placenta. Immunohistochemical staining with antisera against the βA subunit of activin was present mainly in the placental cytotrophoblast, syncytiotrophoblast, and vascular endothelium, and was not associated with an increase in maternal temperature. No significant difference was noted between the two analgesic techniques with regard to maternal temperature elevation. Intrapartum temperature elevation was not associated with histologic signs of placental inflammation or with expression of activin βA in the placenta. Conclusion: Other mechanisms may be involved in the etiology of temperature elevation during labor.