Perineal tears sustained during vaginal birth

Design: Cross-sectional study.

Methods: The sample was composed of 100 women with perineal tears whose length and depth were measured using the tool Peri-Rule™. Bivariate and multivariate analyses were carried out using a significance level of 5% (p = 0.05).

Results: Similar numbers of women sustained single or multiple tears (51% vs 49%). Perineal tears occurred more frequently in the posterior than anterior region of the perineum (80% vs 58%). In 77.5%, 20.0% and 2.5% of the women, first-, second- and third-degree tears, respectively, occurred in the posterior region of the perineum, with over half of them having straight-line tears (62.5%), approximately one third having U-shaped tears (35.0%) and a minority having star-shaped tears (2.5%). Perineal oedema during labour (OR = 5.31) remained an independent predictor of second-degree tears. Infant birth weight (RC = -1.32), perineal body length (RC = 0.41) and oxytocin use (RC = -6.44) were statistically significantly associated with the size of perineal tears sustained.

Conclusion: Perineal tears following normal birth were most likely of the first degree, straight-line and occurred mainly in the posterior region of the perineum. The degree, length and depth of the tears varied according to the location.