Objective: This is a systematic review to assess published scientific evidence on preterm birth predictors.
Methods: An Internet search for predictors of preterm birth was performed and the evidence level of each method was evaluated.
Results: There is strong evidence that preterm birth can be predicted using vaginal sonography to evaluate cervical characteristics, fetal fibronectin in cervicovaginal secretions and interleukin-6 in amniotic fluid. There is consistent evidence that digital cervical examination is a weak predictor, and controversy regarding home uterine activity monitoring. There is scanty evidence about the predictive ability of maternal history and perceptions of symptoms since the study design fails to provide high evidence level.
Conclusion: Cervical evaluation by vaginal sonography, fetal fibronectin and interleukin-6 are the best methods for predicting preterm birth.