AimsCompare vaginal resting pressure (VRP), pelvic floor muscle (PFM) strength, and endurance in women with and without diastasis recti abdominis at gestational week 21 and at 6 weeks, 6 months, and 12 months postpartum. Furthermore, to compare prevalence of urinary incontinence (UI) and pelvic organ prolapse (POP) in the two groups at the same assessment points.MethodsThis is a prospective cohort study following 300 nulliparous pregnant women giving birth at a public university hospital. VRP, PFM strength, and endurance were measured with vaginal manometry. ICIQ‐UI‐SF questionnaire and POP‐Q were used to assess UI and POP. Diastasis recti abdominis was diagnosed with palpation of ≥2 fingerbreadths 4.5 cm above, at, or 4.5 cm below the umbilicus.ResultsAt gestational week 21 women with diastasis recti abdominis had statistically significant greater VRP (mean difference 3.06 cm H2O [95%CI: 0.70; 5.42]), PFM strength (mean difference 5.09 cm H2O [95%CI: 0.76; 9.42]) and PFM muscle endurance (mean difference 47.08 cm H2O sec [95%CI: 15.18; 78.99]) than women with no diastasis. There were no statistically significant differences between women with and without diastasis in any PFM variables at 6 weeks, 6 months, and 12 months postpartum. No significant difference was found in prevalence of UI in women with and without diastasis at any assessment points. Six weeks postpartum 15.9% of women without diastasis had POP versus 4.1% in the group with diastasis (P = 0.001).ConclusionsWomen with diastasis were not more likely to have weaker PFM or more UI or POP. Neurourol. Urodynam. 36:716–721, 2017. © 2016 Wiley Periodicals, Inc.