The role of sonography in predicting cervical dystocia during labor

The work is devoted to the modern knowledge about physiology of labor, about etiology and pathogenesis of labor anomalies. The modern classifications of disturbances of uterine contractions are presented. The following terms are analyzed: dystocia, which literally means hard labor, and cervical dystocia (dystocia of cervix uteri), which means difficult labor due to spasm of the cervix. The modern knowledge about the structure of the uterine cervix is presented, including the data of sonography and the changes of cervix during pregnancy.