Association Between Maternal Bladder Descent Angle and Urinary Incontinence in Late Pregnancy: A Transperineal Ultrasonography Study

OBJECTIVE: To quantitatively evaluate bladder morphological changes induced by fetal head descent during late pregnancy using transperineal ultrasonography (US) and to investigate the association with urinary incontinence (UI). This study aimed to introduce a novel, imaging-based approach for assessing pregnancy-related urinary dysfunction. METHODS: In this study, 14 women with singleton pregnancies beyond 36 weeks of gestation were evaluated. During routine antenatal visits, participants completed a validated questionnaire assessing urinary symptoms, and the bladder descent angle (BDA) was measured using transperineal US. The BDA was defined as the angle between the bladder base and the inferior margin of the pubic symphysis. RESULTS: UI was reported in 57.1% of participants, with stress urinary incontinence (SUI) being the most common subtype (62.5%). Ultrasonography revealed that BDA increased in late pregnancy. The SUI group exhibited a significantly greater BDA compared with the no-UI group (p = 0.03), whereas the overall UI group showed only a non-significant trend (p = 0.081). CONCLUSIONS: The BDA assessed by transperineal US is considered a practical and simple marker for the evaluation of UI.