Early second-trimester inflammatory markers and short cervical length and the risk of recurrent preterm birth

This study aimed to analyze the associations between serum and cervicovaginal inflammatory markers and recurrent spontaneous preterm birth in a cohort study of 62 pregnant women with ≥1 prior early spontaneous birth. Serum samples and cervicovaginal swabs from the women were obtained at enrollment in early second trimester (week 12–25). Cervical length was measured by ultrasound and dicotomized in to short (≤25 mm) and long cervices (>25 mm). The study endpoints were spontaneous preterm birth before 35 weeks and secondarily < 37 weeks. Multiple inflammatory markers in serum (IL-1β, IL-2, IL-5, IL-6, IL-8, IL-12, IL-18, TNF-α, TGF-β, sTNF-R1, GM-CSF and TREM-1) and cervicovaginal secretions (IL-18, sTNF-RI and sIL-6) were individually associated with spontaneous preterm birth. Short cervical length did not explain associations between inflammatory markers and spontaneous preterm birth. Serum and cervicovaginal inflammatory markers did not correlate. In a combined prediction model using both serum and vaginal inflammatory markers, serum TNF-α, cervicovaginal sIL-6Rα and cervical length predicted 69% of all recurrent spontaneous preterm birth at a 5% false-positive rate. In conclusion, cervical length, serum TNF-α and cervicovaginal sIL-6Rα provide a clinically useful prediction of recurrent preterm birth in early second-trimester in women with a prior spontaneous preterm birth.