Objective: To find a biological marker associated with preterm delivery or neonatal infection in pregnant women with preterm labour and intact membranes.
Study design: Cervical secretions were collected from 286 women hospitalized for preterm labour with intact membranes at 24-34 weeks' gestation. The outcomes studied were delivery before 33 and 35 weeks' gestation, chorioamnionitis, and neonatal infection, and their association with the presence of IL-6 mRNA in cervical secretions as detected by RT-PCR. The other infectious markers tested were: bacterial vaginosis and fetal fibronectin in cervical secretions; serum CRP and white blood cell count.
Results: The vaginal secretions of 13 of 286 women (4.7%) contained IL-6 mRNA. The only other marker tested significantly associated with IL-6 mRNA+ was the presence of streptococcus in vaginal secretions (30.8% versus 9.4% in the IL-6+ and-groups, p = 0.03). Although the difference did not reach statistical significance (p<0.06 and 0.08, respectively), in women with IL-6 mRNA in cervical secretions we observed a tendency to give birth before 33 and 35 weeks more often than the population as a whole. This group was at higher risk of neonatal infection (38.5% versus 15.1%; p = 0.04). After adjustment for infectious risk factors, IL-6 remained significantly associated with neonatal infection (OR = 4.6, 95% CI [1.1-18.9]). The sensitivity of IL-6 mRNA for neonatal infection was 11.1%. The specificity was 96.7%.
Conclusion: The detection of IL-6 mRNA by RT-PCR in vaginal secretions allows identification of a small group of women at high risk of neonatal infection, independently of other markers of infection.