Characterization of the inflammatory cytokines in the vagina during pregnancy and labor and with bacterial vaginosis.

Objectives: 1) To characterize the presence of interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in the vagina during pregnancy and in labor; 2) to compare the vaginal levels of these inflammatory cytokines between laboring and nonlaboring patients; and 3) to compare the vaginal levels of these cytokines between women with and without bacterial vaginosis (BV).
Methods: Vaginal fluid was obtained by lavage from pregnant women with intact membranes at various gestational ages and during labor at term. These samples were analyzed for specific cytokine levels using standard enzyme-linked immunosorbent assay techniques. A Gram stain, wet mount, and pH were obtained from the vaginal fluid and were used to diagnose BV. The Mann-Whitney U test was used to evaluate the individual cytokine levels between groups, with P < .05 considered statistically significant.
Results: There was a wide range of vaginal cytokine levels found in our pregnant population (N = 72). Vaginal levels of IL-1 beta (median 1070 versus 245.7 pg/mL) and IL-6 (9.0 versus 0 pg/mL) were found to be significantly elevated in laboring patients as compared with nonlaboring patients (P = .005 and P = .002, respectively). There were no significant differences in the levels of IL-1 alpha and TNF-alpha between the laboring and nonlaboring women. Interleukin-1 beta was also found to be significantly elevated in the group of patients with BV (3364 versus 245.7 pg/mL; P = .01), particularly those who were nonlaboring (P = .003). In each individual patient, there was a wide variation in the levels of the four different cytokines.
Conclusions: Measurable levels of the inflammatory cytokines IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha were present in the vagina during pregnancy and labor. Vaginal levels of IL-1 beta and IL-6 were found to be significantly elevated in laboring patients as compared with nonlaboring patients. Vaginal levels of IL-1 beta were also significantly elevated in nonlaboring patients with BV.