Predictive value of combined cervicovaginal cytokines and gestational age at sampling for intra-amniotic infection in preterm premature rupture of membranes.

OBJECTIVE

To determine whether interleukin (IL)-1β, IL-6, and IL-8 in cervicovaginal fluid, alone or in combination with clinical risk factors, could predict intra-amniotic infection in women with preterm premature rupture of membranes (PPROM).

DESIGN

A prospective cohort study.

SETTING

University teaching hospital.

POPULATION

Women with singleton pregnancies presenting PPROM between 20 and 35 weeks of gestation (n = 76).

METHODS

Cervicovaginal fluid samples were collected for IL-1β, IL-6, and IL-8 measurements immediately before amniocentesis. Amniotic fluid obtained by amniocentesis was cultured and the white blood cell count was determined. Clinical risk factors analyzed included demographics and gestational age. Cervicovaginal concentrations of cytokines were measured using a multiplex bead array assay.

MAIN OUTCOME MEASURE

A positive amniotic fluid culture.

RESULTS

The prevalence of a positive amniotic fluid culture was 46.1% (35/76). Stepwise multivariate regression analysis yielded a model using cervicovaginal IL-6 and gestational age at sampling with the area under the curve (AUC) of 0.807 for predicting intra-amniotic infection. The AUC for this model was significantly higher than either parameter retained in this model but no differences were observed between the AUC of this model based on non-invasive variables, and amniotic fluid white blood cell count using invasive amniocentesis for the prediction of intra-amniotic infection.

CONCLUSIONS

Among measured cytokines, the combination of cervicovaginal IL-6 and gestational age appears to be best in predicting intra-amniotic infection and allows for a considerably better accuracy than the use of either factor alone. Overall, this combination performed as well as amniotic fluid WBC count for predicting intra-amniotic infection.