Ultrasonographic assessment of the uterine cervix and interleukin-8 concentrations in cervical secretions predict intrauterine infection in patients with preterm labor and intact membranes.

OBJECTIVE: Interleukin-8 concentrations in cervical secretions have been related to microbial invasion of the amniotic cavity and histological chorioamnionitis. Since a short uterine cervix may be a risk factor for intrauterine infection, we set out to determine the interrelationship between cervical-secretion interleukin-8 concentration, cervical length measured by transvaginal sonography and intrauterine infection in women with preterm labor and intact membranes. DESIGN: The study group comprised 144 pregnant women admitted to hospital for preterm labor and intact membranes. At admission, interleukin-8 in cervical secretions was assayed. The uterine cervix was evaluated by transvaginal sonography and the cervical index (funnel length + 1)/cervical length) was measured. In all cases, amniotic fluid was obtained by amniocentesis immediately after cervical examination and was cultured for aerobic and anaerobic bacteria including Ureaplasma ureolyticum and Mycoplasma hominis. Placentas were analyzed at delivery for the presence of histological chorioamnionitis. RESULTS: Forty-three per cent (62/144) of pregnancies delivered preterm and 12.5% (18/144) of the amniotic fluid cultures were positive. Placentas were available from 54 pregnancies which delivered preterm and histological chorioamnionitis was found in 59.2% (32/54) of the cases. Interleukin-8 concentrations in cervical secretions were significantly higher in the presence of microbial invasion of the amniotic cavity (median 1191.5 ng/ml, range 812-5234 ng/ml vs. median 109 ng/ml, range 12-2231 ng/ml; p < or = 0.0001) and histological chorioamnionitis (median 982.5 ng/ml, range 430-5234 ng/ml vs. median 435 ng/ml, range 40-1750 ng/ml; p < or = 0.0001). Similarly, higher values for cervical index were obtained in the presence of a positive amniotic fluid culture (median 1.23, range 0.35-5.88 vs. median 0.29, range 0.024-4.85; p < or = 0.0001) or histological chorioamnionitis (median 1.18, range 0.043-5.88 vs. median 0.562, range 0.040-2.48; p = 0.011). Multiple logistic regression analysis indicates significant independent associations with a positive amniotic fluid culture and histological chorioamnionitis for the cervical interleukin-8 concentrations (amniotic fluid culture positive > or = 850, histological chorioamnionitis > or = 450) and for the cervical index (amniotic fluid culture positive < or = 0.58, histological chorioamnionitis < or = 0.56). CONCLUSIONS: Intrauterine infection is associated with increased interleukin-8 concentrations in cervical secretions and a short cervix. Their combined analysis may reduce the indications for invasive procedures and improve the selection of women in preterm labor who may benefit from antimicrobial treatment.

Interleukin-6 concentrations in cervical secretions in the prediction of intrauterine infection in preterm premature rupture of the membranes.

The objective of this study was to determine the value of interleukin-6 (IL-6) in cervical secretion to diagnose microbial invasion of the amniotic cavity in patients with premature rupture of the membranes. Cervical secretions were sampled immediately before amniocentesis in 124 patients with singleton pregnancies and preterm premature rupture of the membranes. Gestational age ranged between 24 and 32 weeks. Amniotic fluid was cultured and IL-6 measured in amniotic fluid and cervical secretions. A total of 33.8% (21/124) of the amniotic fluid cultures had positive results. In cervical secretions the median concentration of IL-6 was 672 pg/ml (range 5-1,250) in the presence of intra-amniotic infection in contrast to 95.5 pg/ml (range 12-640) in women with negative amniotic fluid culture (p 200 pg/ml had a sensitivity of 78.5%, a specificity of 73.1% and a relative risk of 4.6 for intra-amniotic infection. Receiver-operator characteristics curve analysis showed that IL-6 assay in cervical secretions is comparable to IL-6 assay in amniotic fluid in predicting intra-amniotic infection (p = 0.468). In conclusion, intra-amniotic infection is associated with increased levels of IL-6 and concentrations in cervical secretions are related to amniotic levels. The measurement of IL-6 in cervical secretions may help to noninvasively identify intra-amniotic infection among pregnancies with preterm premature rupture of membranes.

The value of transvaginal ultrasonographic examination of the uterine cervix in predicting preterm delivery in patients with preterm premature rupture of membranes.

The objective of this study was to compare the value of ultrasonographic assessment of the uterine cervix and amniotic fluid tests in the prediction of the interval from admission to delivery in patients with preterm premature rupture of membranes. Ninety-two patients admitted to the hospital for preterm premature rupture of membranes between 24 and 32 weeks of gestation underwent both transabdominal amniocentesis and transvaginal ultrasonographic evaluation of the uterine cervix. Amniotic fluid analyses included cultures for aerobic and anaerobic bacteria, mycoplasmas and ureaplasmas, white blood cell count and glucose and interleukin-6 determinations. The ultrasonographic variables evaluated were cervical length, presence of funneling and cervical index ((funnel length + 1)/cervical length). The outcome measure was the interval from admission to delivery. The median interval from admission to delivery was 4.5 days (range 0-36). An abnormal uterine cervix was associated with a short time interval (cervical length < or = 20 mm, median 2 days, range 0-14 vs. median 6 days, range 0-36; p < or = 0.0001; presence of funneling, median 3 days, range 1-31 vs. median 8 days, range 0-36; p < or = 0.001; cervical index > 0.50, median 2 days, range 0-7 vs. median 8 days, range 1-36; p < or = 0.0001). However, interleukin-6 concentration in the amniotic fluid was the best predictor of the interval from admission to delivery when compared to the ultrasonographic indices and to all the amniotic variables considered. Moreover, when a multiple model was applied, the cervical index significantly and independently improved the performance of interleukin-6 in the prediction of the interval from admission to delivery. These data suggest that the combined use of the amniotic fluid interleukin-6 assay and the cervical index in patients with preterm premature rupture of membranes provides a good prediction of the interval from admission to delivery, thus identifying a subgroup of patients at high risk of imminent delivery.

The diagnostic value of interleukin-8 and fetal fibronectin concentrations in cervical secretions in patients with preterm labor and intact membranes.

The objectives of this study were 1) to evaluate interleukin-8 concentrations in cervical secretions in predicting preterm delivery, microbial invasion of the amniotic cavity and histologic chorioamnionitis in patients with preterm labor and intact membranes and 2) to compare the diagnostic value of interleukin-8 with fetal fibronectin determinations in predicting preterm delivery, microbial invasion of the amniotic cavity and histologic chorioamnionitis in patients with preterm labor and intact membranes. Interleukin-8 and fetal fibronectin were assayed in cervical secretions in 106 patients with singleton pregnancies and intact membranes admitted for preterm labor. Amniotic fluid obtained by amniocentesis was cultured and placentas (No = 43) analyzed for the presence of chorioamnionitis. The prevalence of pregnancies delivered preterm was 46.2% (49/106) and 15.09% (16/106) of amniotic fluid cultures were positive. Interleukin-8 levels in cervical secretions were significantly increased in patients who delivered preterm (p < or = 0.0001), in presence of positive amniotic fluid culture (p = 0.0016) and histological chorioamnionitis (p = 0.008) than in patients with negative findings. Receiver-operator characteristics curve analysis showed that an interleukin-8 value > 450 pg/ml is comparable to that of a fetal fibronectin value > 50 ng/ml in predicting preterm delivery (p = 0.247). Among patients who delivered preterm interleukin-8 concentrations > 860 pg/ml predicted a positive amniotic fluid culture with a sensitivity of 81.2% and a specificity 66.6%. Further, in patients who delivered preterm and had a negative amniotic fluid culture, IL-8 concentrations > 480 pg/ml predicted histological chorioamnionitis with a sensitivity 78.5% and specificity 61.5%. A positive fetal fibronectin > 50 ng/ml was not predictve of either a positive amniotic fluid culture or the presence of histological chorioamnionitis. In conclusion, increased concentrations of interleukin-8 and fetal fibronectin are associated with impending delivery and their diagnostic value seems comparable. However, interleukin-8 concentrations identify patients at risk of a positive amniotic fluid culture and the presence of histological chorioamnionitis. Measurement of interleukin-8 in cervical secretion is a non-invasive method to identify patients at risk for both preterm delivery and intrauterine infection.