Efeitos de métodos de preparação perineal isolados versus combinados sobre a distensibilidade perineal e força muscular: ensaio clínico randomizado controlado

Abstract

Introduction: Perineal trauma is a very common condition and is responsible for morbidities, both in the short and long term, in women. Some strategies were developed with the aim of preventing this injury. These include perineal massage and instrument-assisted perineal stretching. However, the literature states only the effects of perineal massage in relation to postpartum variables and is still very controversial about the effectiveness of instrument-assisted perineal stretching and its application time. Objective: Comparing the effects of the instrument-assisted perineal stretching technique with different application times, in combination to perineal massage, and of the isolated techniques in relation to muscle variables and delivery endpoints. Material and methods: This was a controlled, randomized, investigator-blind, clinical trial, with concealed allocation. Ninety-six pregnant women between 18 and 40 years of age, with a gestational age of 33 weeks, pregnant for the first time or with previous pregnancies that ended before the 21st week and with a degree of strength >1 on the modified Oxford Scale, were randomized. The participants were submitted to three evaluations: before the intervention, after four sessions, and after eight sessions. The primary endpoint, distensibility of the perineal region (through Epi-No Delphine Plus®), and secondary endpoint, pelvic floor muscle contraction capacity (through Peritron®), were analyzed. In addition, after childbirth, secondary endpoints related to childbirth (route of delivery and laceration) were evaluated through a questionnaire. After the initial evaluation, the volunteers were randomly assigned to four sample groups: PnM group (n= 24), that underwent perineal massage (for 10 minutes); IStr group (n= 24), that underwent instrument-assisted perineal stretching (for 15 minutes); PnM + IStr 15’ group (n= 24), that used the two previous procedures; and PnM + IStr 2’ group (n= 24), that used perineal massage (for 10 minutes) and instrument-assisted perineal stretching (for 2 minutes). Eight interventions were carried out. Results: For perineal distensibility, an interaction occurred between group and time [F(6.142) = 2.439; p=0.028]. In the second evaluation, a significant increase of this variable was observed in the PnM + IStr 2’ group when compared to the groups that used isolated techniques. In the third evaluation, the IStr 15’, PnM + IStr 15’ and PnM + IStr 2’ groups showed higher values than the PnM group. No interaction between group and time was observed in the muscle strength evaluation, but an effect of the time [F(2.152) = 10.507; p<0.001] and the group [F(3.152) = 13.528; p<0.001] on this variable was identified, and the PnM group was the one that presented the greatest contraction strength. No differences were found regarding the route of delivery (p=0.87) and the degree of perineal laceration (p=0.19). Conclusion: Perineal massage and instrument-assisted perineal stretching, both for 15-minute and 2-minute applications, are capable of increasing the perineal distensibility and PFM strength. The combination of methods seems to be the most effective way to promote results.