Impaired ultrasonographic cervical assessment after voiding: a randomized controlled trial

Area of Science:

• Obstetrics and Gynecology
• Medical Imaging
• Reproductive Medicine

Background:

• Focal myometrial contractions can impede transvaginal ultrasound imaging during pregnancy.
• Optimizing imaging protocols is crucial for accurate obstetric assessments.

Purpose of the Study:

• To determine if the timing of bladder emptying affects focal myometrial contraction development and transvaginal ultrasound image adequacy.
• To evaluate the impact of a delayed voiding interval on imaging outcomes.

Main Methods:

• A blinded randomized controlled trial involving pregnant women (14 0/7-32 0/7 weeks' gestation).
• Participants were randomized to immediate transvaginal imaging (within 5 minutes of urination) or deferred imaging (at least 15 minutes after urination).
• Outcomes included focal myometrial contraction development, image adequacy, and placenta previa diagnosis, analyzed using repeated-measures log binomial regression.

Main Results:

• Women in the deferred scan group had a 30% lower likelihood of focal myometrial contractions and a 41% lower likelihood of inadequate images.
• The likelihood of imaging demonstrating both placenta previa and focal myometrial contraction was significantly reduced in the deferred group (76% less likely).
• Eight women needed to defer imaging for 15 minutes to prevent one instance of focal myometrial contraction or inadequate imaging.

Conclusions:

• A minimum 15-minute interval between bladder voiding and transvaginal cervical evaluation is associated with reduced focal myometrial contractions.
• Delaying imaging after urination improves the adequacy of transvaginal ultrasound images in pregnant women.