Impact of threatened preterm labor and lower genital tract biocenosis on the concentrations of selected proinflammatory cytokines in cervicovaginal fluid of pregnant women

Objective: Recent studies have suggested that proinflammatory cytokines might play a crucial role in the mechanism of preterm labour and delivery. Lower genital tract infection could also influence the cytokines levels. The main aim of this study was to compare the concentrations of interleukin (IL)-1 alpha, IL-1 beta, IL-6 and IL-8 in cervicovaginal fluid of pregnant women with threatened preterm labour (TPL) with group of women with normal course of pregnancy (reference group) and to determine impact of lower genital tract microflora on cytokines concentration.

Methods: Cervicovaginal fluids were obtained by lavage from 40 pregnant women at 22 to 34 weeks' gestation. Those samples were analyzed for the concentrations of selected cytokines using standard enzyme-linked immunosorbent assay technique. Lower genital tract microbiology was diagnosed using Gram stain method according to Spiegel's criteria. TPL was defined as uterine contractions treated by tocolysis.

Results: Threatened preterm labour (TPL) was diagnosed in 22 (55.0%) cases. Mean gestational age at the time of cytokines measurement was 28.6 weeks. Mean concentrations of IL-1 alpha, IL-1 beta and IL-8 measured in cervicovaginal fluid of pregnant women with TPL and in reference group were similar (89.43 vs. 91.17 pg/ml; 42.05 vs. 41.01 pg/ml and 621.8 vs. 697.8 pg/ml, respectively). Vaginal levels of IL-6 was higher among women with preterm labour (21.1 pg/ml vs. 13.9 pg/ml) as compared to reference group. Bacterial vaginosis (BV) was diagnosed in 11 women (27.5%) while grade I microflora in 19 (47.5%). There was a positive correlation between BV and IL-1 alpha and IL-1 beta concentration but no with IL-6 and IL-8.

Conclusions: Vaginal levels of IL-6 were found to be significantly elevated among women with threatened preterm labour while IL-1 alpha and IL-1 beta among women with BV. The usefulness of cytokines measurement in cervicovaginal fluid of pregnant women for prediction of preterm delivery should be clarified in further after excluding the impact of lower genital tract infections on cytokines concentrations.