Interleukin 6 determinations in cervical fluid have diagnostic and prognostic value in preterm premature rupture of membranes

OBJECTIVE: Our aim was to determine whether interleukin-6 concentrations in cervical fluid samples are of value in the identification of microbial inv asion of the amniotic cavity, prediction of the duration of the latency per iod, and assessment of the risk of neonatal complications in preterm premat ure rupture of membranes. STUDY DESIGN: A cohort study was performed in 86 patients with preterm prem ature rupture of membranes. Amniotic fluid and cervical fluid were collecte d. Amniotic fluid was cultured for aerobic and anaerobic bacteria, as well as mycoplasmas. Interleukin 6 was measured by a sensitive and specific immu noassay. The receiver operating characteristic curve, logistic regression, and survival techniques were used for analysis. RESULTS: (1) Patients with a positive amniotic fluid culture had a signific antly higher median cervical fluid interleukin 6 concentration than those w ith negative results (median, 528 pg/mL; range, 174-825 pg/mL; vs median, 1 69 pg/mL; range, 8-986 pg/mL; P < .0001). (2) A cervical fluid interleukin 6 concentration of >350 pg/mL had a sensitivity of 92%:, and a specificity of 78% in the identification of a positive amniotic fluid culture. (3) Pati ents with a cervical fluid interleukin 6 concentration of >350 pg/mL had a significantly shorter median interval to delivery and higher rate of funisi tis, preterm delivery within 2 days and 7 days, and the occurrence of signi ficant neonatal morbidity than did those with a cervical fluid interleukin 6 concentration of <350 pg/mL (P < .05 for each). (4) The increased perinat al morbidity remained significant after adjustment for gestational age (P < .05). (5) There was a strong correlation between cervical fluid concentrat ions and amniotic fluid concentrations of interleukin 6 (P < .001). CONCLUSION: Cervical fluid interleukin 6 determinations are of value in the assessment of the likelihood of microbial invasion of the amniotic cavity, impending preterm delivery, and the occurrence of significant neonatal com plications in the setting of preterm premature rupture of membranes.