The fetomaternal dependency of cord blood interleukin-6

Interleukin-6 (IL-6) plays a major role in hematopoiesis, immune functioning, and the acute phase response. In umbilical cord blood, this cytokine was thought to be a marker of neonatal defense to stress and infection, however, neonatal IL-6 production is immature. We speculated that a maternal influence exists on neonatal IL-6, at least during uncomplicated deliveries. Of the 81 healthy parturients included in this study, 51 delivered vaginally, 20 with and 31 without epidural analgesia, and 30 underwent elective cesarean section, 20 with epidural and 10 with general anesthesia. Maternal blood was sampled on hospital admission and just after delivery. Neonatal blood was collected from the umbilical cord. A significant positive correlation was found between neonatal cord blood interleukin-6 levels and maternal serum IL-6 levels on admission (r = 0.57, p <0.001) and just after delivery (r = 0.79, p <0.001). This was not influenced by the type of delivery or anesthesia. Neonatal IL-6 levels were weakly negatively correlated with the duration of gestation and with the Apgar score 1 min after birth. A fetomaternal dependency of neonatal IL-6 on maternal serum IL-6 levels implies a priming or modulatory role of the maternal immune system on that of the neonate.