Changes in the Angle of Uterine Flexion as the Bladder Fills

The goal of this clinical trial is to evaluate how bladder filling affects the uterine flexion angle in adult nulliparous women with a uterine flexion angle \90°? Participants will: Drink 600 mL of water following a standardized protocol. Undergo repeated suprapubic ultrasound measurements of bladder volume and uterine flexion angle. Remain under observation until urination or for a maximum of 4 hours. No comparison group is included in this study.

Inclusion Criteria: * Adult woman * Nulliparous * Registered with a social security scheme * Uterine flexion angle \< 90°, empty bladder Exclusion Criteria: * Pregnant woman * Woman wishing to become pregnant and currently trying to conceive * Primary amenorrhoea * Menopause * History of surgical termination of pregnancy * History of medical termination of pregnancy * History of hysterectomy * History of conisation * Absence of the uterus * Symptoms of urinary tract infection (gross haematuria, burning on urination, frequent urination) * Under legal guardianship (curatorship, trusteeship)