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 > or =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 (< or =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-1beta, IL-2, IL-5, IL-6, IL-8, IL-12, IL-18, TNF-alpha, TGF-beta, 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-alpha, cervicovaginal sIL-6Ralpha and cervical length predicted 69% of all recurrent spontaneous preterm birth at a 5% false-positive rate. In conclusion, cervical length, serum TNF-alpha and cervicovaginal sIL-6Ralpha provide a clinically useful prediction of recurrent preterm birth in early second-trimester in women with a prior spontaneous preterm birth.