Uterine cervical modifications play a central role in preterm labor and are one of the main indicators for the clinical diagnosis of this syndrome. Modifications of the cervix are either isolated events "cervical incompetence" or associated with cervicovaginal infection, which is an important etiological factor. Furthermore, the extent of cervical modifications in preterm labor is probably related to the prognosis of preterm delivery. Certain developments in the treatment of preterm pregnancy have focused on the uterine cervix (e.g. cervical cerclage, treatment of cervicovaginal infections) and such strategies may facilitate the prevention of preterm delivery. The information currently available emphasizes an independent role for the uterine cervix in preterm labor. As a consequence, it should be realised that even though there is a direct association between cervical modifications and uterine contractions, management of preterm labour must not be directed exclusively at the control of uterine contractions and tocolysis.