Changes in Maternal Serum Levels of C3 and C4 Complement Components in Different Delivery Methods and Postpartum Hemorrhage

Background: Activation of the complement system may play a role in the pathophysiology of human labor. Yet no unanimous conclusion has been drawn. Objective: To compare the differences in maternal complement components C3 and C4 serum levels in cesarean section and the vaginal delivery at term and in the postpartum hemorrhage. Methods: One hundred and sixty six women delivered at term were enrolled in this study. Maternal blood samples were obtained from 47 cases of elective cesarean section and 119 cases of the vaginal delivery. Serum complement levels were measured subsequently by immuno-scatter turbidimetry. Results: The maternal complement levels declined significantly during delivery by both the cesarean section and the vaginal delivery (p＜0.01) in comparison with the baseline. A much larger drop of C3 serum level was found in the postpartum hemorrhage and in the vaginal delivery, and the incidence of the postpartum hemorrhage has a positive correlation with the complement decline rate. Conclusion: The complement system may be involved in the delivery process and represents a predictive value in postpartum hemorrhage.