Numerous clinical studies have been conducted to improve and identify effective prevention strategies in the threat of preterm birth. Among the parameters studied, in addition to the measurement of the uterine cervix and its changes during the three trimesters of pregnancy, the evaluation of the cervical consistency index (CCI), or an ultrasound evaluation of cervical softness, was also proposed.

Reduced CCI values correspond to greater compressibility and cervical softness. Studies conducted to study cervical remodeling on animal models suggest an early increase in cervical softness that begins immediately after conception followed by shortening and dilation in the terminal stages of pregnancy so that minimal changes in cervicometry correspond to a significant increase in cervical softness . Therefore the study of the early stages of cervical remodeling, such as cervical softness through the ICC, could allow to identify in a timely manner women with an increased risk of preterm birth.

The purpose of this study is to define and standardize the transvaginal technique to determine the CCI, its reference range and establish its potential predictive use in the threat of preterm birth before 32, 34 and 37 weeks.

The purpose of this study is to verify the hypothesis that the introduction of a universal screening program with TVU CL and CCI measurement, in the three trimesters of pregnancy, may be associated with a predictive ability to deliver preterm higher than current protocols.