Uterine Anteflexion

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° when the bladder is empty. The main questions it aims to answer are: How does the uterine flexion angle change as bladder volume increases? What bladder volume is needed to obtain 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.