Natural killer cell activity and delivery: Possible influence of cortisol and anesthetic agents - A study on newborn cord blood

The aim of this study was to evaluate the influence of the method of delive ry, the level of cord blood lidocaine, and the cortisol concentration on th e cord blood natural killer (NK) activity in the full-term healthy newborn. We studied healthy newborns delivered by elective cesarean section without labor under general anesthesia (n = 24), delivered by cesarean section und er epidural anesthesia (n = 21), and delivered vaginally with uncomplicated labor (n = 19). The NK cell activity was significantly lower in newborns d elivered by cesarean section under epidural anesthesia than it was in the g eneral anesthesia group, while it was similar to the levels found in vagina lly delivered newborns. The cortisol concentration was highest in the vagin al delivery group (589.2 +/- 200 mmol/l) and lowest in the general anesthes ia group (199.2 +/- 81.9 mmol/l). The mean serum lidocaine concentration wa s 414.1 +/- 370 mu g/l in the epidural anesthesia group and undetectable in the other groups. In conclusion, our data suggest that the cord blood NK a ctivity was significantly influenced by the method of delivery. This effect could be related to anesthetics given to the mother for general or epidura l anesthesia or to the endocrine-metabolic variations observed after differ ent degrees of delivery-related stress. The NK cells being a first-line def ense mechanism against viral infections, the results of this study suggest an association with the occurrence of early perinatal infections, especiall y in preterm infants. Copyright (C) 1999 S. Karger AG, Basel.