Use of Hyaluronidase to Prevent Perineal Trauma During Spontaneous Births: A Randomized,Placebo‐Controlled,Double‐blind,Clinical Trial

Introduction: The purpose of this study was to compare the frequency and severity of perineal trauma during spontaneous birth with or without perineal injections of hyaluronidase (HAase). Methods: A randomized, placebo‐controlled, double‐blind clinical trial was conducted in a midwife‐led, in‐hospital birth center in São Paulo, Brazil. Primiparous women (N = 160) were randomly assigned to an experimental (n = 80) or control (n = 80) group. During the second stage of labor, women in the experimental group received an injection of 20.000 turbidity‐reducing units of HAase in the posterior region of the perineum, and those in the control group received a placebo injection. The assessment of perineal outcome was performed by 2 independent nurse‐midwives. A 1‐tailed Fisher exact test was performed, and a P value < .025 was considered statistically significant. Results: Perineal integrity occurred in 34.2% of the experimental group and in 32.5% of the control group, which was not a statistically significant difference (P= .477). First‐degree laceration was the most common trauma in the posterior region of the perineum in women in both groups (experimental = 56%, control = 42.6%). Severe perineal trauma occurred in 28.9% of the experimental group and 38.8% of the control group, which also was not a statistically significant difference (P= .131). The depth of second‐degree perineal lacerations in the experimental and control groups, measured by the Peri‐Rule, was 1.9 cm and 2.3 cm, respectively. An episiotomy was performed in 11 women (experimental group = 3, control group = 8), and 4 (all in control group) had third‐degree lacerations. Discussion: The use of injectable HAase did not increase the proportion of intact perineum and did not reduce the proportion of severe perineal trauma in our sample.