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

Beth Israel Deaconess Medical Center112 enrolled

Overview

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.

This blinded randomized-controlled trial will be performed through the Division of Maternal Fetal Medicine at Beth Israel Deaconess Medical Center. We will offer enrollment to any pregnant woman at gestational weeks 14+0/7 through 31+6/7 presenting for obstetric ultrasound where cervical assessment and/or placental location determination is indicated. Patient positioning and image acquisition will follow a standard protocol and will be performed by the co-investigators. Outcome ascertainment will be performed by two co-investigators blinded to participant allocation upon completion of data collection. Demographic and obstetrical outcome data will be collected via review of the medical record. Analysis of primary and secondary outcomes will yield incidence data, and comparisons will be made between groups.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Enrollment

112

Conditions

Interventions

Interval bladder emptyingBEHAVIORAL

Participants randomized to the "Interval" arm (cervical assessment 15 minutes or more after voiding) will be notified of their allocation and asked to immediately use the rest room and attempt to void completely. A synchronized clock will be located in this restroom, and each participant will be asked to note the time that she completes voiding. This will be confirmed by the research staff by noting the time the participant enters and exits the restroom. The participant will return to the waiting room or ultrasound room. Any indicated trans-abdominal ultrasound imaging will be performed, and preparations will be made for the vaginal ultrasound. The participant will be asked not to void prior to the vaginal ultrasound. Cervical assessment will take place at a minimum of 15 minutes from voiding time.

Outcomes

Primary Outcomes

Presence of focal myometrial contraction

Focal myometrial contraction as defined by transvaginal ultrasound findings: * Thickening of the myometrial portion of the uterine wall visualized as two distinctly different areas of echogenicity * An unusually long-appearing cervix (possibly more than 50 mm) with an S-shaped endocervical canal and apparent internal os located appreciably cephalad * Asymmetric anterior and posterior lower uterine segment widths cephalad to apparent internal os * The thickening is transient.

Time frame: Throughout the duration of that ultrasound examination (minutes)

Secondary Outcomes

Location of focal myometrial contractions

The location of focal myometrial contractions in relation to the internal cervical os is defined by: * Distance from internal os to caudal-most portion of focal myometrial contraction (measured with a curved line).. * Proportion that lie immediately adjacent to the internal cervical os.