Measurement of Interleukin 8 in Cervicovaginal Fluid in Women With Preterm Premature Rupture of Membranes: A Comparison of Amniotic Fluid Samples

Cervicovaginal fluid (CVF) samples may be a feasible alternative to amniotic fluid (AF) sampling in women with preterm premature rupture of the membranes (PPROMs), because PPROM causes AF to spill into the CVF. We aimed to assess the correlation and limits of agreement of interleukin 8 (IL-8) levels between CVF and AF in women with PPROM and to compare the clinical value of CVF IL-8 to AF IL-8 for the prediction of microbial invasion of amniotic cavity (MIAC). A retrospective cohort observational study was conducted on 85 women with singleton pregnancies (24-34 weeks) presenting with PPROM. The CVF samples were obtained simultaneously with AF samples retrieved by transabdominal amniocentesis. The levels of IL-8 in paired CVF and AF samples were measured with enzyme-linked immunosorbent assay in the same plate in duplicate using the same dilutions. The prevalence of a positive AF culture was 40% (34 of 85). The CVF IL-8 levels were significantly and positively correlated with AF IL-8 levels (r = 0.778). However, the level of agreement between CVF and AF IL-8 levels yielded a Cohen statistic of 0.276. Paired Student t test revealed that the difference between CVF and AF IL-8 levels was statistically significant. The area under the curve for AF IL-8 was significantly higher than that for CVF IL-8 (P = .013). In women with PPROM, IL-8 levels in CVF were significantly correlated with, but were significantly different from, those in AF samples. The CVF IL-8 has moderate predictive capability for the risk of MIAC, but this is inferior to AF IL-8.