Anatomical and functional changes in the lower urinary tract during pregnancy

Area of Science:

• Obstetrics and Gynecology
• Urology
• Pelvic Floor Disorders

Background:

• Urinary incontinence (UI) is a common concern during pregnancy, affecting quality of life.
• Understanding the physiological changes in nulliparous pregnant women is crucial for managing UI.
• The relationship between pelvic floor dynamics and UI in pregnancy requires further investigation.

Purpose of the Study:

• To determine the prevalence of urinary incontinence in nulliparous pregnant women.
• To assess changes in urethro-vesical junction mobility during pregnancy.
• To explore the correlation between UI and urethro-vesical junction mobility.

Main Methods:

• A prospective longitudinal study was conducted with 117 nulliparous pregnant women and 27 controls.
• Urinary incontinence was assessed using questionnaires and 24-hour pad tests.
• Perineal ultrasound measured urethro-vesical junction position and mobility (displacement/pressure coefficient).

Main Results:

• Pregnancy showed a significant increasing trend in urethro-vesical junction angle and displacement/pressure coefficient during coughing.
• Urinary incontinence prevalence was 20% (pad test positive) in pregnant women versus 4% in controls.
• No significant relationship was found between urethro-vesical junction mobility and subjective or objective UI measures.

Conclusions:

• The prevalence of urinary incontinence is significantly higher in pregnant nulliparous women compared to non-pregnant controls.
• Pelvic floor lowering occurs early in pregnancy (12-16 weeks), with decreased pelvic floor muscle contraction.
• Urinary incontinence in pregnancy is likely multifactorial, not solely explained by urethro-vesical junction mobility changes.