Use of transperineal sonography during preterm labor

The gold standard for cervical length (CL) assessment is transvaginal ultrasound scan (TVUS). Transperineal ultrasound scan (TPUS) is an alternative route to CL measurement, which may be more acceptable to women. The primary outcome of this study was to investigate the reliability of TPUS performed by obstetrical team on duty in case of preterm labour (PL) and to compare transperineal to transvaginal CL measurements as a reference. Secondary, we aimed to assess the predictive value of transperineal CL measurement for preterm delivery (PD). Correlation, agreement and patient's preference were assessed. Cut-off points predictive of PD were calculated using receiver-operating characteristic (ROC) curves. Sixty patients admitted with PL were included. Median CL measurements with TPUS and TVUS were 25.3 mm and 27.3 mm, respectively. Correlation was significant (R = 0.95; p  < 0.0001; [95% CI = (-0.032-0.170)]. The cut-off point was 25 mm for TPUS and 22.8 mm for TVUS. In case of PL, CL measurement with TPUS seems reliable and can be performed by the obstetric duty team.