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 invasion of the amniotic cavity, prediction of the duration of the latency period, and assessment of the risk of neonatal complications in preterm premature rupture of membranes.

STUDY DESIGN

A cohort study was performed in 86 patients with preterm premature rupture of membranes. Amniotic fluid and cervical fluid were collected. Amniotic fluid was cultured for aerobic and anaerobic bacteria, as well as mycoplasmas. Interleukin 6 was measured by a sensitive and specific immunoassay. 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 significantly higher median cervical fluid interleukin 6 concentration than those with negative results (median, 528 pg/mL; range, 174-825 pg/mL; vs median, 169 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) Patients with a cervical fluid interleukin 6 concentration of >350 pg/mL had a significantly shorter median interval to delivery and higher rate of funisitis, preterm delivery within 2 days and 7 days, and the occurrence of significant neonatal morbidity than did those with a cervical fluid interleukin 6 concentration of <350 pg/mL (P <.05 for each). (4) The increased perinatal morbidity remained significant after adjustment for gestational age (P <.05). (5) There was a strong correlation between cervical fluid concentrations 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 complications in the setting of preterm premature rupture of membranes.