Objective: The purpose of this study was to determine if refraining from coached pushing during the second stage of labor affects postpartum urogynecologic measures of pelvic floor structure and function. Study design: Nulliparous women at term were randomized to coached (n = 67) vs uncoached (n= 61) pushing. At 3 months' postpartum women underwent urodynamic testing, pelvic organ prolapse examination (POPQ), and pelvic floor neuromuscular assessment. Results: Urodynamic testing revealed decreased bladder capacity (427mL vs 482 mL, P = .051) and decreased first urge to void (160 mL vs 202 mL, P = .025) in the coached group. Detrusor overactivity increased 2-fold in the coached group (16% vs 8%), although this difference was not statistically significant (P = .17). Urodynamic stress incontinence was diagnosed in the coached group in 11/67 (16%) vs 7/61 (12%) in the uncoached group (P =.42). Conclusion: Coached pushing in the second stage of labor significantly affected urodynamic indices, and was associated with a trend towards increased detrusor overactivity. © 2005 Elsevier Inc. All rights reserved.