Background: Differences in cytokine distribution across different biological fluids; maternal plasma, cervicovaginal fluid (CVF), and amniotic fluid are evident throughout normal pregnancy, but profiles of numerous cytokines varied across trimesters in women delivering term versus preterm in both CVF and serum.
Objective: To evaluate cytokine profile in cervicovaginal fluid (CVF) of women had previous preterm birth (PTB) and the effect imposed by cerclage on these levels.
Patients and Methods: Seventy study women with previous PTB and currently had cercical length (CL) of <25 mm and 20 control women with no history of PTB and had CL of >25 mm were studied. At the 24th gestational week (GW; T1), all women had CL estimation and CVF sampling. At time of labor or removal of the suture (T2), study women had CL re-estimation and CVF re-sampling. CVF levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 were ELISA estimated. Shirodkar cervical cerclage (CC) was performed within 4 days after T1 sampling. Outcomes included difference in T1-CVF cytokines' levels between study and control women, effect of cerclage on CL and CVF cytokines' levels and the value of T1-CVF cytokines' levels as predictors of pregnancy duration.
Results: T1-CVF levels were significantly higher in study than control women and to their T2- levels. T1- and T2-CL in study women was significantly shorter than T1-CL in controls with significant difference between T1- and T2-CL. Percentage of T2-CL decrease was negatively correlated with the percentage of decrease of T2-CVF levels. Duration of pregnancy of study women was negatively correlated with percentage of CL shortening, while was positively correlated with percentage of decrease of T2-CVF levels of MCP-1 and TNF-α. Statistical analyses defined high T1-CVF levels of MCP-1, IL-β and TNF-α as significant early predictor for PTB.
Conclusion: High CVF cytokines' levels were associated with increased risk of PTB. Cerclage worked beyond its mechanical action through reduction of CVF cytokines' levels. High CVF cytokines' levels at 24th GW, especially high levels of MCP-1 and TNF-α, may help to predict PTB.