Dysregulation of inflammation is suspected as a cause of adverse pregnancy outcomes; however, limited data exists describing inflammatory cytokines during the course of uncomplicated pregnancies. Our objectives were to assess longitudinal patterns and associated variability of suspected inflammatory cytokines throughout a normal pregnancy.METHODS:
We recruited 30 women with low risk pregnancies prior to 14 weeks gestational age at a large teaching hospital. Plasma levels of nine cytokines (GCSF, IFNg, TNFa, TGFb, IL1b, IL6, IL8, IL10, and IL23) were monitored in samples collected at five prenatal visits, at mean GAs of 11, 17, 25, 31, and 36 weeks. The longitudinal patterns of cytokines were analyzed using repeated measures ANOVA, and intraclass correlation coefficients were estimated using assessments of variation among women (between subject) and during pregnancy (within subject).RESULTS:
Mean levels were significantly different between visits for IL6 (P<.01), IL8 (P=.04), GCSF (P<.01) and TGFb (P=.02) and displayed distinct patterns with levels increasing throughout pregnancy. ICC estimates ranged from 0.27 (for TGFb) to 0.74 (for IL23), indicating substantial and statistically significant intra-pregnancy variability when compared to the inter-pregnancy variability of cytokines Il1b, IL6, IL8, IL10, IFNg, and TGFb.CONCLUSION:
Levels of specific inflammatory cytokines vary throughout the course of a normal pregnancy and have distinct patterns. Along with the significant within-person variability of cytokines in pregnancy, these findings suggest the importance of longitudinal risk assessment to reflect trajectories and address random variability. Further studies are needed to assess the significance of longitudinal cytokines in pregnancies complicated by preterm birth.