The significance of interleukin-6 concentrations in cervicovaginal fluid: its relation to umbilical cord plasma and the influence of antibiotic treatment

This study was performed to correlate cervicovaginal fluid and umbilical cord plasma level of IL-6 and IL-8 in patients with premature rupture of the membranes (PROM) and to see the effect of antibiotics on those concentrations. As a part of a randomized controlled trial of treatment in PROM with antibiotics, cervicovaginal fluid was sampled before delivery for measurement of IL-6 and IL-8 and for bacteria from 36 patients less than 36 weeks of gestation. Umbilical cord plasma was also collected. Concentrations of IL-6 and IL-8 were measured by an ELISA. Neonatal infections were noted in a total of 9 cases, including bacteria detection (Escherichia coli 2 cases, GBS and Streptococcus constellata) in 4 cases. Correlation between IL-6 in cervicovaginal fluid and in cord plasma (r = 0.881, p < 0.0001) was stronger than that of IL-8 (r = 0.469, p < 0.01). The difference of concentrations in IL-6 and IL-8 was not significant between cases with (n = 20) and without (n = 16) ampicillin. Our observation indicates that the measurement of IL-6 concentrations in cervicovaginal fluid is a useful marker for PROM patients who are more likely to develop neonatal infection and the antibiotic treatment does not necessarily produce their beneficial effects on fetuses at the risk of infection.