Levels of cytokines in umbilical cord blood in relation to spontaneous term labor.

OBJECTIVE: Inflammatory mechanisms are thought to play an important role in the process of labor, both in preterm and spontaneous term delivery. We aimed to determine whether normal spontaneous vaginal delivery (SVD) at term was associated with an inflammatory activation compared with elective cesarean section (ECS) without previous onset of labor.

METHODS: Cytokine concentrations were measured in venous cord blood obtained from 60 term newborns (ECS, n=35; SVD, n=25) born to mothers with clinically uneventful pregnancy and without signs of infection.

RESULTS: Both study groups showed no differences in birth weight, umbilical artery pH, Apgar at 5 min, and gender distribution. Infants delivered by ECS had lower gestational age: mean, 38.5 weeks (range, 37.0-39.6 weeks) vs. mean, 39.8 weeks (range, 37.9-42.4 weeks) (P<0.001). Concentrations of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p40, IL-12p70, IL-17, IL-1 receptor antagonist, soluble IL-2 receptor α, granulocyte-macrophage colony-stimulating factor, interferon (IFN)-α2, IFN-γ, tumor necrosis factor (TNF)-α, TNF-β, and interferon inducible protein 10 were not different between ECS and SVD. Newborns after SVD displayed increased levels of transforming growth factor β1 (TGF-β1): mean, 8580 pg/mL (95% CI, 5554-11,606) vs. mean, 4864 pg/mL (95% CI, 2471-7257) (P<0.0012).

CONCLUSIONS: Our findings suggest that, in healthy, term neonates, the exposition to normal spontaneous delivery and labor is not associated with systemic activation of different inflammatory mediators compared with ECS except for TGF-β1. Further studies are needed to evaluate the immunomodulatory role of labor-associated TGF-β1 increase in fetal cord blood.