Elastography of the uterine cervix: implications for success of induction of labor.

Abstract

To perform a preliminary investigation into the use of elastography for cervical assessment, in order to determine the effectiveness of this method for the evaluation of cervical consistency. Elastography of the uterine cervix was performed in 29 patients before induction of labor, with tissue surrounding the internal os described using a numeric scale called the elastography index (EI). A color map from purple to red was produced with the hardest tissues displayed as purple and assigned a score of 0 points and progressively softer tissues displayed as blue (1 point), green (2 points), yellow (3 points) and red (4 points). The EI of tissue around the internal os, in the middle part of the cervical canal and around the external os were analyzed in relation to the success of induction of labor using the t-test. The mean EI of the internal os in the group of patients with successful induction of labor was 1.23, while in the group with failed induction of labor it was 0.39 (Student's t-test, P=0.024). No difference was found for the EI of the middle part of the cervical canal or for the EI of the external os in relation to the success of induction of labor (P>0.05). Elastography of the uterine cervix may be an objective method for assessment of softening of tissue in the region of the internal os before induction of labor. Standardization of the cervical properties observed on elastography during pregnancy may help to guide the use of prostaglandins or oxytocin for induction of labor.