Focal Myometrial Contractions: Impact on Cervical Assessment and Association With Voiding

Focal myometrial (uterine) contractions occur in a substantial number of vaginal ultrasound examinations and can impede accurate cervical length measurement and placental location determination. The timing of bladder voiding is associated with the prevalence of focal myometrial contractions on vaginal ultrasound cervical assessment. We propose a blinded randomized-controlled trial of bladder voiding immediately before vaginal ultrasound for cervical assessment compared with no bladder voiding immediately before vaginal ultrasound in order to determine the prevalence of focal myometrial contractions during vaginal ultrasound cervical assessment and test whether timing of bladder voiding is associated with their incidence.