Ultrasound assessment of urethral structure and bladder neck position in women with different parities

Introduction and hypothesis: The study aims to compare the urethral sphincter size and bladder neck position and mobility in women with different parities.

Methods: Women referred to the urodynamics clinic for lower urinary tract and prolapse symptoms were included in the study. A detailed history was taken, and transperineal two- and three-dimensional ultrasound was performed on all the women. The women were divided into four groups according to the vaginal parity. Group 1 had no vaginal childbirths. Group 2 had one, group 3 had two and group 4 had three or more vaginal childbirths. The data was analysed and compared among the groups.

Results: One hundred fifty women were included in the study. There were 34, 22, 48 and 46 women in groups 1 to 4 respectively. The distribution of different urodynamic diagnoses was similar in all four groups. The urethral sphincter measurements were significantly larger in the vaginally nulliparous group than in all other groups. The measurements were not smaller in multiparous women than in primiparous women. The bladder neck was at a lower position at rest in parous women than nulliparous women. The bladder neck movement was not more in groups 2 to 4 than in group 1.

Conclusion: The urethral sphincter was smaller and the bladder neck position was lower in parous women than nulliparous women. These differences were not progressive with increasing parity. Request for elective caesarean section during the second pregnancy to protect the urethra is not supported by this study.