The effect of childbirth on urethral mobility: a prospective observational study.

PURPOSE

Vaginal delivery confers a higher risk of stress urinary incontinence than cesarean section. This may be mediated by impaired urethral support and consequent urethral hypermobility. We evaluated the effect of childbirth on urethral mobility.

MATERIALS AND METHODS

We examined 488 nulliparous women 36 to 38 weeks and 4 months postpartum by interview and 4-dimensional translabial ultrasound. Urethral mobility was described by vectors of movement from rest to the maximum Valsalva maneuver of 6 equidistant points from bladder neck to external urethral meatus using the formula, [Formula: see text] . Peripartum changes in urethral mobility were correlated with delivery data.

RESULTS

Of the 367 women who returned for followup at a median of 4.1 months 187 (51%) underwent normal vaginal delivery, 54 (15%) underwent vacuum/forceps delivery and 126 (34%) underwent cesarean section. A total of 32 women (15%) complained of new onset postpartum stress urinary incontinence. A generalized increase in urethral mobility was observed after childbirth (each p <or=0.003), which was associated only with delivery mode at the proximal urethra (p <or=0.02). Peripartum changes in urethral mobility did not differ significantly between women with and without de novo stress urinary incontinence (each p >0.6).

CONCLUSIONS

There seems to be a generalized increase in urethral mobility after childbirth but this change does not seem to be associated with de novo SUI.