To characterize immune modulation as expressed by cytokine assays at three time-points in human pregnancy.This is a prospective, longitudinal study of a broad panel of cytokine expression during singleton pregnancies resulting in an uncomplicated, full-term, live births. Peripheral blood was obtained at 8–14, 18–22, and 28–32weeks gestation. Six cytokines – IFN-γ, IL-4, TNF-α, IL-1β, IL-6, and IL-10 – were measured in supernatants obtained from whole blood stimulations with PHA or LPS and were compared to unstimulated controls. Samples were processed by Luminex-100 MAP®. We used Generalized Linear Models (GLM) to evaluate cytokine trajectories.Complete data were obtained for 45 uncomplicated pregnancies. Overall, peripheral blood WBC’s demonstrated dampened cytokine responses. However, over the course of pregnancy, we found enhanced counter-regulatory cytokine expression (e.g., shown by increased IL-10).The overall decrease in pro-inflammatory cytokines and increase in counter-regulatory cytokines as uncomplicated pregnancy progresses supports the evolving concepts of immunoregulation for the maintenance of a viable pregnancy.