The Final Stretch: Range of Normal Perineal Changes During Second Stage Labor in First Vaginal Birth

The Final Stretch: Range of Normal Perineal Changes During Second Stage Labor in First Vaginal Birth: "Purpose: The aim of this descriptive, observational study is to identify the range of perineal changes during second stage labor and associated perineal outcomes. Background: Many women fear pelvic floor damage as a consequence of vaginal birth despite limited evidence of a causal link between vaginal birth and pelvic floor damage. Documentation of the process of perineal stretch, which is presumably when damage would occur, is absent from the literature. Methods: Eighteen nulliparas were observed during second stage labor. Documentation of position, pushing, time of vertex being visible, crowning, rate of distention, color changes and blanching was noted with each push. Descriptive statistics were calculated. Results: Second stage length ranged 15-281 minutes (mean 94). Ratio of time the vertex was visible to a sustained crown was 0% to 75% of the total time in second stage. The ratio of time spent with the vertex in a sustained crown ranged from 3% to 48% of second stage duration. Despite variance in duration of stretch, longer duration did not correlate with perineal trauma. Blanching, duration of active pushing, and rate of distension were associated with increased risk of trauma. Conclusions: A wide range of “normal” perineal changes during second stage was documented that do not lead to lacerations. Future studies should identify opportunities to prevent perineal trauma beyond focusing duration of perineal stretching."